Reducing Crashes on Urban Arterial Roads

Although fatal crashes are more likely to occur on rural arterial roads, most occur on urban streets due to the sheer volume and frequency of traffic. This week’s blog will be a ‘two parter’, exploring how arterial roads can be improved to reduce crashes from a traffic engineer’s perspective.

According to the Insurance Institute for Highway Safety (IIHS), most drivers within the USA travel 80% more on urban arterials than rural. Across the entire country, about two billion vehicles travel on about 143,000 miles of urban arterials on a daily basis and have a reported 8,000 fatal and 1,000,000 non-fatal injury crashes annually.

Crashes on arterial roads can become exceedingly serious in nature. Most of these roads weren’t designed to accommodate the current vehicle capacity and road infrastructure within the US has been deteriorating. Crashes can also be the result of a number of causes such as driver error, traffic violations, deteriorating road conditions, design of the infrastructure and more. Traffic engineers have a number of tools and strategies at their disposal in order to reduce crashes and safety issues on urban arterial roads.


Data Collection to Understand Urban Arterials

Traffic data collection should be completed on the arterial to understand the current traffic flow. Turning movement counts and average daily traffic counts will provide the necessary data to start understanding the traffic volumes that the engineer will have to work with in order to maximize the current infrastructure while decreasing any safety concerns. Using automated traffic data collection equipment such as Miovision’s Scout video based solution allow traffic engineers to collect both traffic study types without the hassle of manual, on-site data collection.

Reviewing previous police crash reports of an arterial can provide a lot of detailed information that traffic engineers generally don’t have access to. The IIHS recommends obtaining at least three years of reports which will provide observations by police and witnesses and help identify recurring problems.


Identifying Crash Patterns through Data Collection

According to the IIHS, all urban crashes can be classified as one of 13 types based on vehicle movement and driver behaviour prior to the crash. Each intersection of the arterial should be reviewed to understand which crash types are most prevalent and traffic engineers can start identifying crash patterns. This will help identify the arterial problem(s) and potentially the appropriate solutions.

The next step would be to observe the traffic and relate it back to the problems that were identified through the data that was collected earlier. It’s important to establish the problems from the data collection first in order to understand what to look for on-site. For example, frequent rear-end crashes may indicate the absence of accommodations for turning vehicles. Being able to see the actual traffic flowing through the arterial can showcase the problems and answer any questions the traffic engineer might have.

Using Miovision’s automated traffic data collection equipment provides traffic engineers with a video record of the traffic studies which can be reviewed from the office. It eliminates having the need for on-site observation and can provide additional insight into the activity that occurred during the traffic studies.

Developing Measures to Reduce Crashes

Comparing the traffic and data collected will help identify the current issues of the road for creating a safety improvement plan. For example, if there are a high number of rear-end crashes then traffic engineers might consider improving traffic signal visibility, increasing yellow signal duration, improving the coordination of signal timing, installing skid-resistant pavement, introducing turn lanes if none exist, and/or making sure signs are clear to drivers. Below are a few suggestions by the IIHS for addressing three types of crashes and possible solutions.

In order to start the process of reviewing an arterial, data collection is crucial. It provides capacity and traffic volume information that is important to understand and include in moving forward with a safety improvement plan. Using Miovision’s automated traffic data collection provides an accurate process in collecting turning movement counts and average daily traffic counts. The video based solutions provide an easy and convenient way to review the arterial traffic activity without needing to be on-site.


Check out next week’s second part to this blog which will review specific examples of how safety improvement plans have been implemented by traffic engineers.


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