This summer MnDOT work crews began testing a
state-of-the-art intrusion alarm system developed by defense industry
contractors. The system detects the speed and trajectory of approaching
vehicles. If there’s a threat, it alerts at-risk construction workers, who are
tracked and notified via warning devices attached to hard hats or vests. The
system also transmits audio and visual warnings to the oncoming vehicle.
Learn more at “A New System for Reporting Driver Intrusions into Work
Zones.”
A manufacturer’s video (available at
bit.ly/AWAREvideo) shows the Advanced Warning and Risk Evasion system, which
uses multiple radar detectors to detect speed, position and trajectory of up to
64 vehicles over 600 feet.
 TRAFFIC & SAFETY — A significant number of fatal crashes on rural Minnesota roads come from vehicles running off the road at a curve. Because it’s not economical to install infrastructure like a sensor-triggered dynamic warning display on low-traffic roads, researchers have been investigating an alternative: warnings inside vehicles that are delivered from a smartphone (or ultimately through a system built into the car). Learn more at “System Uses Smartphone App to Warn Drivers of High-Risk-Curves.”
TECHNICAL SUMMARY 2018-12
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TRAFFIC & SAFETY – Minnesota’s
high-occupancy toll (HOT) lanes have safely improved traffic capacity. But
during heavy traffic, driving speeds can vary dramatically between HOT and general
purpose lanes, and drivers moving into HOT lanes can force other drivers to
brake suddenly. New software developed at the Regional Transportation
Management Center (RTMC) enables traffic engineers to model the impact of
changing lane access from open (allowing traffic to enter the HOT lane at any
point along a given corridor) to closed (allowing traffic to enter only at
certain points). Making this change in access only requires restriping and replacing
signage, and can easily be done in response to changes in traffic patterns that
affect mobility and safety.
TECHNICAL SUMMARY 2018-11
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MULTIMODAL – The Twin Cities metropolitan area freight network
is vital to keeping Minnesota companies in business. But many of the network’s
roadways are overcapacity at peak travel periods, and heavy truck traffic is
only expected to increase. In a recent project, investigators built on the
results of previous studies to analyze mobility, reliability and delay along
key freight corridors. This analysis dovetails with federal guidelines (NCHRP
Research Report 854) for identifying and addressing truck bottlenecks caused by
weather, roadway geometry, weight limits and other factors.
TECHNICAL SUMMARY 2018-15
MATERIALS &
CONSTRUCTION – MnDOT developed
its own concrete pavement design software, MnPAVE-Rigid, in 2014, which
incorporates federal mechanistic-emperical design guidance adapted for Minnesota
conditions. An upgrade was needed, however, to improve usability and expand the
range of inputs for traffic, subgrade type, base type and thickness. The new
MnPAVE-Rigid 2.0 software is not only
easier to use, it allows concrete pavement designers to select from more options
for aggregate base types and pavement thicknesses, and use actual rather than
estimated traffic values. Researchers developed the software on Java 2.0, which
allowed MnDOT to avoid expensive systems and enables the agency to upgrade the
software internally as needed. Learn more at “Upgrading MnPAVE-Rigid Design
Software.”
TECHNICAL SUMMARY 2018-17
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 MATERIALS
& CONSTRUCTION — Since 1995, MnDOT has
required frost-free materials—coarse gravel, sand and other materials—in
asphalt pavement subgrades at depths of 30 to 36 inches, based on load requirements.
Whether this practice was effective at all locations was unclear, however, and
sometimes it was unnecessary. To determine necessary pavement structure requirements,
researchers studied 72 Minnesota sites with different soil and pavement types
to develop pavement profiles that looked for correlations between winter ride
quality and construction characteristics. Learn more at “Design
Spreadsheet Offers Alternatives to Protect Pavements from Frost Damage.”
TECHNICAL
SUMMARY 2018-06
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MAINTENANCE & OPERATIONS – Maintenance crews often spray pavement surfaces with a “fog” of liquid sealant after the pavement has been in service for a year or more. These fog seals extend the water resistance of asphalt and protect pavements from oxidation. However, the seals are dark mixtures that interfere with pavement striping visibility and can also reduce roadway friction. Researchers investigated bioseals, which are currently more expensive than petroleum industry products but do not obscure markings. Study results showed that bioseals temporarily reduced the retroreflectivity of pavement markings and still reduced friction to some extent, though not by as much as traditional seals. The traditional seals offered longer lasting water resistance. The new sealant technology will be useful in some areas such as city streets and will provide some advantages over traditional fog seals.
TECHNICAL SUMMARY 2018-18
9/12
LRRB RIC fall meeting, St. Cloud
10/17
LRRB fall meeting, Stearns County
10/23-24
Toward Zero Deaths Conference, Mankato
10/31
MnDOT TRIG meeting, Arden Hills
11/1
CTS Transportation Research Conference, Minneapolis
11/1
National Cooperative Highway Research Program (NCHRP) problem statements due
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