Decriminalization of Marijuana and Potential Impact on CMV Drivers

by Kathryn Slater, UMTC Research Staff

Captain Darrin Grondel is the Director of the Washington Traffic Safety Commission and a Captain with the Washington State Patrol. At the 2016 Commercial Vehicle Safety Research Summit, Captain Grondel discussed drugged driving and its impact on traffic safety. The following are some highlights of Captain Grondel’s presentation.


As marijuana becomes legal for recreational use across the country, transportation safety stakeholders grapple with the realities and challenges inherent in the new legislation. Currently, the possession and use laws in the U.S. are described as a patchwork, as their look and structure remain very different, depending on the state.

What’s more, the strength of marijuana has changed dramatically over the last several decades. While most governmental studies involving marijuana involve THC levels of 3-6%, the substances now showing up in a variety of forms (oils, edibles, vaping) have THC levels closer to 30-40%.  While many issues around legalization of marijuana remain unclear, what we do know is that incidences of drugged driving are going up, and must be mitigated.

The overarching issue around legalization of marijuana remains the existing knowledge gap around the effects of cannabis (and other drugs) on driving. One reason for this gap is a complete lack of data around drugged driving; including crash and inspection data, and information about the types of drugs being used, and in which combinations.

Another major issue is public indifference. Drivers tend to see drunk driving as clearly dangerous and socially unacceptable, but don’t feel strongly one way or the other about drugged driving. Many people don’t know the level at which drugs impair them, and haven’t been educated about the dangers of driving while taking something as benign-seeming as cough medicine. The Pacific Institute for Research and Evaluation conducted the PIRE Roadside Survey in 2014 and 2015, where they surveyed 926 drivers in 5 counties. Of drivers who said they’d used marijuana within two hours of driving, 67% said that it made no difference in their driving. Knowing what we do about the effects of THC on the brain, it seems unlikely that drivers would be unaffected.

What remains clear is that drugged driving is much more complicated than drunk driving, and that these types of crashes are on an upward trend. Less clear, are the details around how drivers are affected, how long those effects last and how police will know a drugged driver when they see one.

2016 Commercial Vehicle Safety Research Summit

The University of Massachusetts Traffic Safety Research Program (UMassSafe) held a Commercial Vehicle Safety Research Summit in November of 2016 to promote best practices for advancing safety through partnerships among law enforcement and state driver’s license agencies with universities.  With more than 100 attendees from across the Northeast, the 2-day Summit, funded by the Federal Motor Carrier Safety Administration (FMCSA), addressed key issues related to crash prevention including driver distraction and autonomous vehicles, as well as homeland security, drugged driving, social media and workforce development.


“Innovation is rapidly changing the transportation sector.  The Federal and state governments must keep up while never losing sight of protecting the traveling public,” said FMCSA Deputy Administrator Daphne Jefferson, one of the keynote speakers. “This summit enables us to learn from each other and build partnerships with universities to realize the safety benefits of innovation and automation.”

The goals of the summit were based upon the premise that an integrated approach and effective partnerships can reduce the number of truck and bus crashes and fatalities.  Massachusetts has enjoyed positive safety results because of the successful partnership that now exists between UMassSafe, the Massachusetts State Police Commercial Vehicle Enforcement Section and MassDOT’s Registry of Motor Vehicles Division. Using this experience as an example, summit organizers encouraged other state participants to develop or expand the connection between universities and state agencies involved in crash prevention efforts.

The FMCSA funded project continues with the implementation of a UMassSafe Technical Assistance Center (TAC) in order to provide assistance for law enforcement and licensing agencies as well as universities, acting as a resource and information center building on the momentum of the Summit.  Additional information can be accessed at

By: Robin Riessman, UMassSafe

Glow-in-the-dark Lighting Lanes for Safety

This past fall at Texas A&M University, glow-in-the-dark markings were used on the green bike lanes at an unsignalized intersection. The intersection chosen was a Dutch junction which protects cyclists from motorists at the intersection and increases the visibility of cyclists during turning maneuvers. This type of markings can enhance the safety and usability of bike infrastructure. The technology is based on phosphors, a material which is used in glow sticks, televisions, and computer screens.


Photo Source: Texas A&M Transportation Institute

Similarly, in Lidzbark Warminski, Poland, the same technology was used to illuminate a separated bike and pedestrian path. The 330 foot-long, 12 foot-wide path was illuminated to create a bike lane and a pedestrian lane. The city plans on using this stretch as a pilot study.


Photo Source: Strabag

While there are many ways to light a bike lane, there are several advantages to this method. This technology can provide continuous lighting relative to street lights, reduced light pollution for surrounding homes, ability to light paths in remote locations without electrical service, and the use of renewable energy reducing potential climate change impacts.

Both of these projects are pilot studies and are primarily focused on testing how long the product will last under the wear and tear of cyclists and weather. Texas A&M has only installed the glow-in-the-dark markings at one intersection on campus and the stretch illuminated in Poland is limited to just 330 feet. This technology is very new and has limitations for wide spread use due to cost. In Massachusetts where winter months can result in additional stress on pavement due to snow and ice, implementation of this technology could be costly and might be better used strategically rather than as a standard method for all bike paths and lanes. Glow-in-the-dark pavement markings may be ideal in areas with high volumes of cyclists, on bike paths adjacent to residential neighborhoods, and college campuses where the technology could also be used on crosswalks. It will be interesting to follow the findings of these pilot studies in Texas and especially Poland, which shares a similar climate as Massachusetts.