Patterns of movement in cities, especially office job commutes, were substantially altered in 2021 by telework, economic change, and other responses to COVID-19, according to new research from the Accessibility Observatory at the University of Minnesota. While the immediate effects of these behavioral changes, such as reduced congestion and lower transit ridership, have been well documented, new data reveals deeper impacts that differ by the three modes studied: auto, transit, and biking.
Aging pavement infrastructure and the deterioration of pavement surfaces over time remain an ongoing challenge in meeting roadway user expectations. Preventive pavement preservation treatments that are applied on sound, structured-condition pavements can extend the pavements’ functional service life and reduce future maintenance costs. Fog seals are one of these treatments. Fog seals are applied by spraying a thin layer of emulsion onto the pavement to slow or in some cases reverse the damage caused by oxidative aging. Asphalt emulsions are the most common material used in fog seals. Rejuvenators are usually added to the formulation to lower its viscosity and possibly even rejuvenate the surface of the existing aged pavement.
Speed limits are a popular safety measure used in urban areas. A new analysis that monitored driving speeds before and after posted changes to speed limits reveals lower speed limits may not, at least initially, cause drivers to slow down.
MnDOT maintenance practitioners and managers are always looking for new and better ways to handle winter weather. A recent evaluation of new products revealed which of several new pieces of high-potential winter maintenance equipment were appropriate for use on Minnesota highways. Just as importantly, the agency uncovered the shortcomings of other equipment, identifying critical issues to address before acquiring additional equipment.
As bridge infrastructure in Minnesota and across the country ages, maintaining and preserving the existing bridge network becomes increasingly important—and increasingly challenging. In Minnesota alone, 25 percent of bridge-deck area is more than 50 years old, and the number of bridges rated in “fair” condition has recently overtaken the number rated in “good” condition.
When a transportation innovation shows potential for significantly increasing safety, implementation may seem like the obvious next step. But without public support, a project can be met with resistance that results in delays, additional costs and a lost opportunity to save lives.
Providing traffic control in work zones is one of the highest risk jobs in the country. Flaggers are often considered the first line of defense against distracted, inattentive or aggressive motorists who may intrude into these work areas. A new, cost-effective system that tracks an oncoming vehicle’s trajectory can warn workers of an unsafe intrusion into the work zone and alert drivers to slow or stop.
As the demand for aggregate in construction increases, recycling concrete waste as aggregate has been recognized as an environmentally sustainable solution with potential cost savings. It would allow recycling of construction and demolition waste and reduce some of the need to quarry and haul virgin aggregate. However, the use of recycled concrete aggregate (RCA) has been limited by concerns over its quality and performance, and by lack of uniform specifications as to what kind and how much of the aggregate to use in pavement construction. Studies and on-the-ground experience have shown that high levels of RCA reduce the durability of pavements. The effects of lower replacement levels have not been well documented, however.
Snowplow operators work in difficult, often low-visibility conditions. A new system assists drivers in knowing their lane position and warns of approaching obstacles. After operators tested the system over two winters, researchers gathered feedback, revised the system and readied it for the next step in statewide deployment.
Crossroads 