- Road Safety Audit: What is it and how does it work?
- The 8 Steps of a Road Safety Audit Process
- Driving Data, Road Safety Audits and the Safe System
Road safety audits are essential to any road safety strategy. A multidisciplinary team of experts analyzes a planning project or specific location from a variety of angles and viewpoints. Using different types of information, they provide recommendations on how to improve safety for all road users. Data, and specifically driving behavior data, is a new source of information that experts can now consider in this context. Driving data makes the assessment of potentially risky road zones more accurate and responsive. It also helps in evaluating the impact of safety measures once they’ve been implemented. Driving data is essential to proactive road safety, which is integral to the Safe System and meeting Vision Zero goals.
Road Safety Audit: What is it and how does it work?
The FHWA defines a road safety audit as,
“a formal safety performance examination of an existing or future road or intersection, by an independent, multidisciplinary team that qualitatively estimates and reports on potential road safety issues and identifies opportunities for improvements in safety for all road users.”
What kind of road projects?
Road safety audits can be performed at any stage of a road safety engineering project, from planning and early design to existing locations. The projects themselves can range from a minor intersection to retrofitting for new multimodal uses, or major new infrastructure developments.
Road Safety Audit Objectives
Including all road users and circumstances in their scope, road safety audit objectives are always twofold:
1/ Identify as accurately as possible
● where there are safety concerns on the road
● to what extent
● for which users
● and under what circumstances.
2/ What options exist to remove or lessen the identified safety concerns and improve traffic management.
The Importance of a Road Safety Audit
Pedestrians, bikes and other non-motorist road users accounted for 20.3 percent of traffic deaths in 2019, up from 15.5 percent in 2010*. As more people adopt active transportation methods, road safety audits have a large part to play in ensuring safety for all. Audits make it possible to identify, remove or control hazards that could poorly impact physical assets and people, whether they’re in the public or private domain.
Driving Data’s Role in the Road Safety Audit
This is where driving data can make a noteworthy difference. It helps experts first in accurately locating those hazards. It then measures whether recommendations, once implemented, have alleviated the danger.
The 8 Steps of a Road Safety Audit Process
Driving data supplements the eight steps of a road safety audit process in four major ways: collecting information, supporting analysis, providing key facts that validate the analysis and can be presented to stakeholders, and measuring the impact of recommendations once they have been implemented.
Step 1/ Define the project.
An intersection, a large road area, or at the project stage. Fixing the scope focuses the road safety vision.
⇒ Driving data’s additional – and new – perspective
Driving data records driving behavior. When drivers brake or accelerate harshly, swerve, or drive distractedly, and when this behavior occurs repeatedly in the same location, it can suggest near-crashes. Driving data is therefore a new source of information that helps to identify areas where road safety is a concern – before any car crashes happen.
Step 2/ Create the team.
All members are specialists in a different discipline. They may be experts in road safety, traffic operations, road design, bike and pedestrian safety, transit operations, enforcement, or emergency medical services. None are otherwise involved with the project in question. Their expert views and independent roles allow them to freely analyze the project from all angles, and find the opportunities that will solve or reduce the safety concerns.
⇒ The innovation or data expert’s role
An innovation or data expert has knowledge of the latest technologies available that can help make the road safer for all road users. Including one on the panel of experts ensures that current data sources are combined with traditional data sets, for a fuller and completely up-to-date picture of the project’s safety concerns.
Steps 3 & 4/ Collect and aggregate data, and meet to discuss.
Team members begin their analysis using a variety of data sources. These can include the following.
● Observation data: speed surveys, vehicle yield rates, cyclist and pedestrian behavior, feedback from road users and from other DOTs… Road experts also visit the location at various times for further understanding. They draw on their knowledge, assumptions and experience built up over their career to analyze the situation.
● Roadway data: road labs can analyze road status in terms of maintenance: roughness, pothole identification, asphalt quality… 3D road scanning can also be used to provide information on road surface use, traffic signs, road markings, public lighting, advertising, trees – anything on or beside roads. The scans create a complete 3D map of an area that can be consulted at any time.
● Traffic data: information on speed versus posted limits, how lanes are organized and their widths, rights-of-way, road assets such as signalization, parking, bike and pedestrian facilities and any discontinuities, transit stops, traffic flows and volumes at different times of the day…
● Crash data: a minimum of three years is recommended, and five to ten years is best. Crash data is available from the Fatality Analysis Reporting System and includes information from police crash reports, medical examiner reports, emergency medical services reports, state highway department data and state driver licensing and vehicle registration files. Based solely on the analysis of crashes involving a motor vehicle on a roadway open to the public and involving a death, crash data does not take into account other types of accidents: material damage, non-fatal injuries or near-crashes.
⇒ Collecting Near-Crash Information with Driving Data
Adding driving data to the above data sets brings actual driver behavior at the location into the picture. Driving behavior data can be aggregated across all road users. It can also be contextualized, to include weather conditions, the time of day, the day of the week… Analyzing aggregated, contextualized driving behavior can highlight where and when near-crashes occur, and bring ready-to-use insights to address safety problems. Combined with past crash data, up-to-date driving data adds complementary and revealing information that helps experts in identifying and characterizing risk areas.
Step 5/ Analyze data.
For analysis, the team looks at all the data that they have available to them. On the GIS, they can visualize the roadway, road assets, studies and crashes. They can also consult the 3D area map. Assembling everything together as layers of information and combining it with their observations allows experts to deeply analyze all aspects of a location. They are able to focus on what specific measures will increase safety, and in what way.
=> Driving Data about Driving Behavior allow for Deeper Analysis
From here, experts can go even deeper in their analysis. Driving data gives contextual and statistical information that helps experts finetune their understanding. They are able to identify and recommend preventive road safety measures.
Steps 6 & 7/ Present findings and prepare a formal road safety audit report.
The team summarizes its analysis to highlight safety concerns and makes recommendations for road safety improvements. The objective is to be sure that the final report addresses the initial scope and objectives. The project owner decides which recommendations to follow.
=> Fact-Based Measures thanks to Driving Data
The experts can present driving data and the facts it provides about actual driving behavior on the road to back up their analysis. Team members have concrete information in the form of KPIs – the context, intensity, repetition and location of driving events – on which to base their recommendations, and stakeholders their decisions.
Step 8/ Implement – and with driving data, evaluate the impact
Sometimes a public meeting can be organized to share information and gain support. Recommendations are implemented afterward. Experts may need to wait another year or two, waiting for new car crash data, before assessing the impact of implementations.
=> Driving Data Quickly and Easily Visualizes the Impact of Changes
A few months later, using before-and-after analysis, driving data can once again be consulted to determine the impact that implemented recommendations have had on road safety. Stakeholders can proceed through iterations as they monitor their progress, proactively improving safety on their roads. From driving data, they also and once again have the facts that demonstrate the value of the improvements.
Driving Data, Road Safety Audits and the Safe System
The Safe System and Vision Zero focus on a proactive approach to road safety. Road safety audits are essential to promoting awareness of safe design practices, integrating multimodal safety concerns and considering the human factor from all angles. Incorporating driving data and near-crashes bolster road safety audits in their preventive approach to road safety.
*https://www.pedbikeinfo.org/factsfigures/facts_safety.cfm (accessed 4/04/2022)