See how researchers at the Roadway Safety Institute (RSI), led by the University of Minnesota, are working to reduce crashes and save lives on our nation’s roadways in a new video.
The video features RSI director Max Donath and researchers from across the region who are working on a breadth of projects, ranging from reducing crashes at rail grade crossings to improving road safety on tribal lands. The video also highlights a few of RSI’s education efforts, including a museum exhibit designed to introduce preteens to safety concepts.
RSI was established as the Region 5 University Transportation Center in 2013 and is housed at CTS. MnDOT is a key partner for RSI, funding a variety of safety-focused projects by RSI researchers.
If you have spent any time driving on Minnesota roads and highways lately, you know that road construction work zones are all over the place. They can contribute to traffic delays and require vigilance to ensure the safety of both drivers and workers.
MnDOT and the Minnesota Local Road Research Board (LRRB) are doing their best to make work zones more efficient and safer for crew members and the traveling public alike.
Here’s a roundup of some of the great work zone safety projects under way or recently completed:
City and county workers sometimes have trouble determining how to select the appropriate work zone for low traffic roads. The Minnesota Local Road Research Board (LRRB) recently published two supplemental guidebooks to help local agencies identify the appropriate work zone layout for low-volume urban and rural roadways based on the maintenance activity. The guides are intended to supplement MnDOT’s 2014 Temporary Traffic Control Zone Layouts Field Manual.The LRRB has also requested changes to the field manual for low-volume roadways in a letter to the MN Committee on Uniform Traffic Control Devices.
MnDOT is testing a system on I-94 this summer that it hopes will reduce work zone crashes by raising driver awareness of upcoming congestion. Systems with the same purpose have been tested in rural work zones, but mostly applied to locations where backups were predictable.
The Smart Work Zone Speed Notification System will take a different approach, informing drivers of the speed ahead, as opposed to a variable speed limit system tested previously on I-94, which also detected congestion but provided advisory speeds to drivers. It is envisioned that the new system will have greater success in reducing rear-end crashes on large, urban freeway work zones.
The new system is being tested and evaluated on I-94, east of downtown St. Paul, during work to replace and repair the roadway.
Police enforcement and speed limits are the main method of reducing the speed of drivers in Minnesota work zones. While this practice is effective, reducing speeds by approximately 10 to 15 mph, it is not practical to staff every work zone with law enforcement. As an alternative, some states are using automated speed enforcement cameras in work zones.
Automated speed enforcement cameras have been shown to reduce speeds in work zones, but such research did not evaluate how the cameras impact driver attention.
This study explored driver awareness and found that automated speed enforcement cameras in work zones are not a source of driver distraction. It also revealed differences in work zone driving behavior: Older drivers were least able to follow another vehicle closely, while younger drivers were least likely to monitor their speed carefully.
Work zone intrusions — when traveling vehicles enter the work space of a work zone — are a clear safety concern even if they do not result in an accident, and they may indicate locations where future accidents are likely.
MnDOT was interested in learning how other state DOTs collect work zone intrusion data, both the technology used for data collection and the specific information they collect.
This Transportation Research Synthesis (TRS), completed in June 2015, surveyed state DOTs and conducted follow-up interviews with states that collect work zone intrusion data. The survey found that the relatively small number of states that do collect intrusion data typically do so via paper or electronic form.
As a result of the TRS, a recently funded research project proposes to develop a simple method to track and gather information on work zone intrusions. The aim of this process will be to produce a reporting interface (in the same vein as the Crash Report Usability And Design Project for the Department of Public Safety) that gathers essential information without being onerous to work crews.
Training was provided to introduce MnDOT maintenance workers to Automatic Flagger Assistance devices, which can improve safety in work zones by allowing flaggers to provide traffic guidance without having to be in the flow of traffic.
Using a remote control, a single worker can easily operate two AFADs simultaneously, freeing up personnel to perform other tasks and speed up the completion of a road project, the pilot study found. MnDOT estimates that the resulting cost savings can cover an AFAD’s purchase costs within two years.
MnDOT has planned a project to determine whether it is feasible to use a self-propelled device to push or pull an AFAD so it can be used in moving operations such as patching potholes or cracks, which make up more than half of MnDOT’s flagging operations.
In a study released in February 2014, researchers developed and tested a new system to provide audible messages to visually impaired pedestrians for navigating work zones.
The system uses Bluetooth beacons attached to work zone infrastructure that sends messages to a pedestrian’s smartphone app rather than the traditional method of beeping buttons that announce a message when pressed.
By creating a tactile vibration and sound, rumble strips effectively alert distracted drivers to potential danger. However, they are not suitable for moving operations because repositioning them is too labor-intensive. MnDOT needed a method of alerting drivers about upcoming work zones that is more dynamic than
static signs but is portable and can be used in a moving work zone.
The Intelligent Drum Line system, developed in a 2012, could significantly improve work zone safety by relaying audible and visual warnings from traffic drums to speeding drivers as they approach. Further development is needed to ensure the system is cost-effective and portable to serve MnDOT’s needs.
Bees, butterflies and other pollinators busily work on our behalf to help our crops and wild plant life reproduce. Most plants cannot produce fruits and seeds without the aid of these little bugs.
MnDOT is taking steps to ensure that the habitat these creatures depend on gets the protection it needs.
In addition to recently signing an agreement with five other state DOTs to improve pollinator habitat along Interstate 35, a key migratory corridor for Monarch butterflies, MnDOT has just completed a review of other state and local government practices to identify more opportunities to use existing right-of-way to protect pollinators.
MnDOT set out to learn about the experiences of other state departments of transportation and local agencies in maintaining pollinator landscapes on highway rights of way through partnerships with individuals, groups or local agencies.
Results of the literature review are supplemented with findings from a survey of selected state DOTs and Minnesota counties. Nine state DOTs describe current practices or plans to develop new pollinator-specific partnerships; existing partnerships that have been expanded to address pollinators; and Adopt-a-Highway programs that support maintenance of vegetation in the right of way.
The Transportation Research Synthesis (TRS) may lead to enhancements to MnDOT’s existing practices or the development of a new pollinator-specific partnership program.
While MnDOT does not have a community partnership that focuses solely on promoting pollinator habitat, its Community Roadside Landscape Partnership Program allows Minnesota communities to partner with MnDOT to establish and maintain landscaping in the ROW along highways that traverse their communities, and these landscaping treatments may benefit pollinators.
MnDOT has also partnered with the Minnesota Board of Water and Soil Resources and the Minnesota Department of Natural Resources to establish more than 20 native seed mixes for use on Minnesota roadsides. MnDOT’s online PlantSelector tool includes a seed mix tab to help designers and novices select the right seed for the right place.
Project champions take previously proven concepts and help MnDOT turn them into useful practices and procedures to make the state’s transportation system better. Funds can be used for equipment, consultant services or researcher assistance.
“The research implementation program fills the gap between research and deployment of new methods, materials and equipment,” Bruce Holdhusen, MnDOT Research Services senior engineer, said.
Here are the 12 newly funded research implementation projects by category:
Bridge and Structures
Improving Quality of Bridge Inspections Using Unmanned Aircraft Systems (UAS)
Prestressed Concrete Beam Shear Rating
OmniScan Phased Array Ultrasonic Corrosion Imaging System
MnDOT Slope Vulnerability Assessments
Ultra-thin Bonded Wearing Course (UTBWC) Snow and Ice and Wind Effects
Materials and Construction
Cold In-Place Recycling (CIR) for Bituminous Over Concrete (BOC)
Geogrid Specification for Aggregate Base Reinforcement
Balanced Design of Asphalt Mixtures
Cone Penetration Testing (CPT) Design Manual for State Geotechnical Engineers
Policy and Planning
One-year Pilot Test and Evaluation of ASTM DOT Package Compass Portal
Traffic and Safety
Improve Traffic Volume Estimates from Regional Transportation Management Center (RTMC)
Understanding Pedestrian Travel Behavior and Safety in Rural Settings
The report details how the transportation system can accommodate such imminent innovations as autonomous vehicles, mobile web services, mobility as a service, information and communication advances, infrastructure sensors and energy and fuel alternatives.
For example, researchers predict that driving faces near-extinction by 2040, when non-autonomous vehicles will no longer be allowed on public roads at most times. As a result, total transportation-related fatalities may drop 90 percent, road geometry, sightlines and other design priorities may shift, and capacity and speed limits will likely increase on most major roadways.
Unmanned Aerial Vehicles (Drones)
When it comes to drones, MnDOT is already conducting important research that the rest of the nation is closely following. Tara Kalar and Jennifer Zink from MnDOT, and Barritt Lovelace of Collins Engineers, spoke about their efforts at last month’s conference.
Last year, MnDOT Research Services published a report titled “Unmanned Aerial Vehicle (UAV) Bridge Inspection Demonstration Project” that detailed how MnDOT could use drones to perform bridge inspection functions. The initial research project tested one drone’s capability in a variety of bridge inspection scenarios last summer at four Minnesota bridges.
In November, researchers conducted a second research phase to test a more specialized drone at the Blatnik Bridge in Duluth that coincided with that bridge’s regularly scheduled inspection.
A few weeks ago, researchers secured funding to conduct a research implementation project that aims “to implement a statewide UAS (unmanned aircraft systems) bridge inspection contract, which will identify overall cost effectiveness, improvements in quality and safety, and future funding sources for both state and local bridges,” according to the project proposal.
Benham’s talk also addressed 3-D printing, which Chad Hanson, a District 6 project manager, has already used successfully.
Hanson spoke at the conference about his experience using 3-D printing to create a model of the Red Wing Bridge project that brought the project idea to life. According to Hanson, the model enhanced public engagement and informed preliminary design efforts for the bridge.
Partners, stakeholders and members of the public could see, touch and hold the 3-D printed models, which accentuated the project’s engagement process.
To mark Earth Day 2016, MnDOT Research Services is taking a glance at five stellar examples of current research projects at MnDOT that involve pollution control, wetland mitigation, road salt reduction and new ways of recycling pavement.
Soil carried away in stormwater runoff from road construction sites can pollute lakes and rivers.
Stormwater settling ponds provide a place for this sediment to settle before the water is discharged into local bodies of water. However, since stormwater ponds have limited space, a mechanism is needed to remove clean water from the pond to prevent the overflow of sediment-laden water.
MnDOT-funded researchers designed temporary stormwater ponds with floating head skimmers that can remove clean water from the surface of the settling pond, using gravity to discharge water into a ditch or receiving body.
The study, which was completed in spring 2014, identified five methods for “skimming” stormwater ponds that can improve a pond’s effectiveness by 10 percent. MnDOT researchers also created designs for temporary stormwater ponds on construction sites with the capacity to remove approximately 80 percent of suspended solids.
These designs will help contractors meet federal requirements for stormwater pond dewatering. Researchers also determined how often a pond’s deadpool must be cleaned, based on watershed size and pool dimensions.
Stormwater can pick up chemicals and sediments that pollute rivers and streams. Roadside drainage ditches, also known as swales, lessen this effect by absorbing water. But until recently, MnDOT didn’t know how to quantify this effect and incorporate it into pollution control mitigation measures.
In a study completed in fall 2014, researchers evaluated five Minnesota swales, measuring how well water flows through soil at up to 20 locations within each swale.
A key finding: grassed swales are significantly better at absorbing water than expected, which may reduce the need for other, more expensive stormwater management practices, such as ponds or infiltration basins.
This could save MnDOT and counties significant right-of-way and construction costs currently expended on more expensive stormwater management techniques.
Road salt is used for de-icing roadways during winter months, but can have a negative impact on the environment.
This research, which was just approved for funding through the Minnesota Local Road Research Board in December 2015, will investigate the reduction in road salt application during winter months that can be attained with permeable pavements, while still providing for acceptable road safety.
Some initial investigations (see previous study) suggest that road salt application can be substantially reduced, even eliminated, with permeable pavement systems. The proposed research will investigate this hypothesis more thoroughly, and further document the reduction in road salt application that can be expected with permeable pavement.
Road construction in northeast Minnesota often causes wetland impacts that require expensive mitigation. However, borrow areas excavated for road construction material can be developed into wetland mitigation sites if hydric vegetation, hydric soils and adequate hydrology are provided. Fourteen wetland mitigation sites were constructed north of Virginia, Minnesota along the U.S. Trunk Highway 53 reconstruction project corridor and evaluated for wetland. The sites were established with the goal of mitigating for project impacts to seasonally flooded basin, fresh meadow, shallow marsh, shrub swamp, wooded swamp, and bog wetlands. All but one of the sites consistently meet wetland hydrology criteria.
The sites contain a variety of plant communities dominated by wet meadow, sedge meadow, and shallow marsh. Floristic Quality Assessment (FQA) condition categories for the sites range from “Poor” to “Exceptional.”
According to the research report published in March 2016, these sites have shown the potential for creating mitigation wetlands in abandoned borrow pits in conjunction with highway construction. Adaptive management, particularly water level regulation, early invasive species control, tree planting, and continued long-term annual monitoring can make mitigation sites like these successful options for wetland mitigation credit.
MnDOT already extends the lives of some old concrete highways by paving over them with asphalt instead of tearing them up. Now MnDOT hopes to add a third life for these old concrete roads by using a process called cold in-place recycling to re-use that existing asphalt pavement when it reaches the end of its life.
Cold in-place recycling (CIR) uses existing pavements, without heat, to create a new layer of pavement. It involves the same process of cold- central plant mix recycling (which is being employed by MnDOT for the first time on two shoulder repair projects this year), but it is done on the road itself by a train of equipment. It literally recycles an old road while making a new road.
CIR has been in use in Minnesota for 20 years, but only with hot-mix asphalt (HMA) over gravel roads. The purpose of a new study, which was approved for funding in April 2016, is to validate Iowa’s promising new practice using CIR on bituminous over concrete.
In this research project (see proposal), MnDOT will use cold-in-place recycling to replace the asphalt pavement on a concrete road and then evaluate it for several years, comparing it also with control sections.
Along with the potential of a better service life, the cost of CIR is much lower than new hot mix asphalt (HMA). Therefore, a 20-percent to 30-percent price reduction per project may be realized.
Southwest Minnesota has the highest average wind speeds in the state—bad news for MnDOT snowplow operators who often drive in low visibility to clear roads.
“We have more days when the wind blows than when it doesn’t,” said Chase Fester, MnDOT District 7 transportation operations supervisor. “We struggle with the wind.”
That’s why District 7 is piloting a snowplow driver-assist system (DAS) developed by University of Minnesota researchers to combat the blowing snow and fog that often cause zero visibility. The DAS helps snowplow operators see the road alignment and features, such as turn lanes, guardrails, and road markings. Even in less extreme winter weather, snowplow operators gain assurance of their lane location using the system.
The DAS was developed and refined over the past 20 years under multiple research projects funded by MnDOT and the USDOT’s University Transportation Center program. Professor Max Donath, director of the University of Minnesota’s Roadway Safety Institute, led the work. In addition to plows, the DAS technology has also been applied in other specialty vehicles such as patrol cars and ambulances. Numerous vehicles using the system have been deployed in both Minnesota and Alaska.
The DAS uses GPS technology and a front-mounted radar to provide an image of the road and any obstacles in front of the operator. The image is displayed on a monitor inside the cab of the plow. The system also vibrates the operator’s seat as a warning if the plow veers too close to the roadway’s centerline or fog line.
“If the driver gets within one foot of the fog line on the right side, the right side of the seat vibrates. If the driver gets too close to the centerline on the left side, the left side vibrates,” said Fester.
The vibrations continue until the driver moves back into the center of the lane. The driver can also turn off the warning feature to clear snow from the shoulder.
The DAS is currently installed in one truck in District 7. The $75,000 cost makes it difficult to install in every truck in the district or the state, although having at least one system in every district may be possible, Fester said.
Fester said the system proved its worth one day in February when blizzard conditions caused zero visibility and forced many road closures in southwest Minnesota. He was called out at 2 a.m. Feb. 8 to assist a stranded state trooper and several motorists on a 12-mile stretch of Hwy 60 between Windom and Heron Lake. Fester drove a pickup behind the DAS-equipped snowplow, driven by Darryl Oeltjenbruns, to reach them.
As the DAS identified stranded vehicles on the way to Heron Lake, Fester and Oeltjenbruns checked to make sure they weren’t occupied with people. Once they made it to Heron Lake, they stopped at the community center, where the state trooper and the stranded motorists he brought in were located.
On the way back to Windom, Fester and the state patrolman continued to check on stranded vehicles as the DAS-equipped snowplow led the way. If the vehicles weren’t in the ditch, motorists drove behind the two MnDOT vehicles. If their vehicles were in the ditch, motorists rode in a Suburban that was also being escorted to Windom. After returning to Windom, the motorists were dropped off at motels or truck stops.
“When we first went out, there were about six stranded vehicles. Coming back from Heron Lake, there were about 15,” Fester said. “At one time, we had 12 vehicles in line as we drove back to Windom, driving about 10 to 15 miles per hour.”
Later that morning the DAS system was used again to locate other motorists.
“We continued to use it until about 10 a.m. or 11 a.m. that day,” Fester said. “The system worked great and kept everyone safe. It was an interesting morning.”
(Reprinted and adapted with permission from an article by Sue Roe in MnDOT’s Feb. 17, 2016 Newsline.)
Today, moving freight accounts for more than a third of the world’s transport energy—and that share is growing. The rise in global trade, online retailing, and business-to-business delivery is not only changing how goods are moved but also the type of goods moved and how far or frequently they are transported.
Currently, this massive movement of goods throughout the economy relies on an intricate—and largely decentralized—multimodal network of truck, rail, ship, and airplane delivery. However, change is on the horizon. In a study sponsored by MnDOT and the Minnesota Local Road Research Board, U of M experts outline the important impacts these changes will have on the road network and transportation infrastructure.
“There is hope that new methods of organization and proposed standardization will increase efficiency of freight movement and give rise to a new era of goods transport,” says Adam Boies, an assistant professor in the Department of Civil, Environmental, and Geo- Engineering (CEGE). “In the years to come, we expect that advances in logistics systems will be enabled by new technologies, approaches, and the desire for increased efficiency.”
Changes in the way logistics operations are organized will help drive advances. New information technology permits the sharing of data between and across businesses, which in turn drives efficiency and leads to fuller vehicles. “This may reduce the distance traveled by heavy goods vehicles per unit of GDP, which may in turn reduce costs and entice more demand for delivered goods,” says CEGE professor David Levinson, the study’s principal investigator. “Ultimately, this could mean fewer trips by individual consumers and more deliveries. We anticipate the result will be a net reduction in distance traveled.”
The study also examined some of the potential drivers for changes in the freight industry as a result of logistics reorganization. These include supply chain pooling, in which individual logistics operations are shared between collaborators, and the Physical Internet Initiative, which seeks to create standards for packaging to enable the homogenization of freight technology. “While both of these advancements have the potential to increase logistics efficiency by reducing the transportation of empty loads, they will also increase truck weights—which may increase pavement damage,” Boies says.
Other transportation and logistics changes will result from shifts in the ways businesses and consumers receive goods and services, including business-to-business systems and technologies that enable a sharing economy, same-day delivery services, 3-D printing, and “last mile” delivery services. In addition, a growing portion of purchases can be delivered directly over the Internet. “Delivery is easily automated for data-based goods like books, music, video, and software,” Levinson says. “Purchases that could once only be completed by moving things can now be done by moving data.”
The benefits of living snow fences and other snow control tools to keep roadways clear of blowing and drifting snow have been known for decades, and MnDOT has been using a variety of these techniques for years to catch snow before it gets to a road.
Living snow fences often consist of trees, grasses and even corn stalks left standing in a farmer’s field. Now willow shrubs are being added to the list as a fast-growing, inexpensive snow control measure.
Researchers recently completed a study that investigated whether willow shrubs could make good living snow fences. While typical snow-fence plants, such as dogwood or cranberry shrubs, can take five to 20 years to establish themselves, shrub willows were effective at trapping snow after just two growing seasons, according to the study.
In spring 2013, researchers installed three varieties of shrub willow side-by-side in two-row and four-row configurations along about a quarter of a mile of Highway 14 in Waseca, where snow drifts are an issue. In April 2014, they cut the shrubs down to the ground to encourage branching and bush density. Though the trimmed willows had little impact on drifting snow the first winter, each willow-shrub plot was collecting two to three metric tons of snow by the second winter, according to the research report. Researchers believe that after three or four growing seasons the willow shrubs could catch the entire mean annual snowfall on the site.
In the four-row configuration recommended by researchers, costs of raising, furnishing, planting and mulching came to about $3.60 per plant, which is dramatically less than the contract bid cost for traditional living snow fence species that cost more than $50 per plant. In addition, the willow shrubs could be harvested and sold as biomass every few years to provide an income source.
Willow trees is just the latest advancement in the state’s snow control program. A 2012 research project evaluated the costs and benefits of living snow fences and provided MnDOT with a payment calculator to determine how much to compensate landowners for installation and maintenance costs.
MnDOT has used these tools and other promotional efforts to nearly double the number of farmers with contracts for corn rows enrolled in the Living Snow Fences program.
The willow species recommended by researchers will be evaluated further in 2017 when they install it as a living snow fence on a new construction site on Highway 60 between Windom and Mountain Lake. Researchers also recommend a future study to compare volume of road salt use before and after installation. They also want to look into identifying appropriate buffer distances to keep willow roots from interfering with cropland root systems.
The mix of fuels used to power the vehicles on our nation’s roadways is diversifying rapidly. While gasoline and diesel are still dominant, an increasing percentage of vehicle power is coming from alternatives such as biofuel, natural gas, and electricity. What could this shift mean for Minnesota’s transportation future? MnDOT and the Minnesota Local Road Research Board turned to U of M experts for analysis.
“The rise of alternative fuels is something we need to keep a close eye on, because it presents a number of issues that may significantly alter our state’s transportation system,” says Adam Boies, an assistant professor in the U of M’s Department of Civil, Environmental, and Geo- Engineering (CEGE).
Minnesota leads the nation in biofuel use, in part due to a series of legislative acts designed to encourage ethanol production and consumption. Boies predicts, however, that biofuel consumption in the state is near saturation and that future shifts will likely be between biofuels. “These shifts may alter the routes of heavy-goods vehicles in the state as refineries shift from corn and soy to fuels derived from agriculture wastes and forest byproducts,” he says.
If the price of natural gas remains significantly lower than diesel fuel, natural gas vehicles will likely make up an increasing share of the heavy-duty vehicle fleet in Minnesota. A larger natural gas refueling infrastructure will need to be developed, most likely by private organizations that manage fleets of vehicles. “As this happens,” Boies says, “efforts must ensure that natural gas vehicles and refueling infrastructure do not emit significant quantities of methane, which has a high global warming potential.”
Minnesota electric vehicle sales have lagged behind the nation—winter temperatures are one factor—but Boies expects the numbers to rise. He estimates 16 percent of new cars sold in Minnesota in 2035, and 56 percent in 2050, will be electrified. The growing numbers will require a more robust charging infrastructure, likely supplied or subsidized by government agencies, he says.
In the long term, on-road charging systems are being investigated. In these systems, under study in several countries, charging coils embedded within the roadway transfer power wirelessly to vehicles. “The systems could make electric vehicles drastically more efficient by reducing vehicle battery size,” he says.
Better vehicle efficiency is likely to continue the trend of falling fuel tax revenues. “Minnesota will need a method for producing revenues from electric vehicles to maintain long-term funding for the transportation road network,” he says. “Currently the higher price of electric vehicles results in increased revenues during vehicle registration, which tends to offset the difference in fuel tax revenues. However, as the price differential between electric vehicles and traditional vehicles shrinks, there will be decreased funding for Minnesota roadways unless additional revenue sources are found.”
Finally, emphasis on fuel efficiency in the light-duty and heavy-duty vehicle fleets will drive the weight of these vehicle segments in opposite directions. “Light-duty vehicles will get lighter and heavy-duty vehicle fleet operators will lobby for increased weight limits on Minnesota roadways to reduce the energy intensity of goods deliveries,” Boies says. “This growing disparity in weight between the two vehicle classes may require increased safety measures to reduce the severity of crashes between vehicle classes.”
“The question of how alternative fuels and electric vehicles will impact the transportation system, ownership models, and operating costs, as well as vehicle and driver safety, are extremely important topics to study,” says Ken Buckeye, MnDOT program manager. “The potential for these trends to impact our revenue streams is also very significant. When you couple those trends with the federal mandate for a CAFÉ standard of 56 mpg by 2025, we are likely to see some profound impacts that reach across modes, jurisdictions, and funding mechanisms.”
Boies’s research is part of a multi-pronged study funded by MnDOT and the LRRB that analyzed the technological shifts altering surface transportation and the implications for Minnesota. Other contributors included CEGE professor and principal investigator David Levinson and associate professors Jason Cao and Yingling Fan of the Humphrey School of Public Affairs. Their high-level white papers are compiled in a final report: The Transportation Futures Project: Planning for Technology Change.