Monitoring and Evaluating Progress towards Vision Zero
How are we tracking progress towards Vision Zero?
FATAL AND SERIOUS INJURY CRASHES AS OF * DATE*
Crashes at this time last year
Embed of dashboard to go here
Number of Safety Projects:
Dollars for Safety Projects:
Number of Safety Projects:
Dollars for Safety Projects:
Over the last year, Atlanta developed and piloted a project evaluation framework to assess the success of projects. The goals of the One Atlanta Strategic Transportation Plan goals and the Downtown Resurfacing Project helped identify KPIs and their relative importance, or weighting. The project evaluation framework examines safety performance among the KPIs. The safety related metrics include both observed outcomes in crashes that occurred at and near the project and crashes predicted using Safety Performance Functions. These safety related KPIs are the most heavily weighted KPIs followed by multimodal access. This weighting reflects the safety-focused and multimodal goals from the guiding documents and establishes a basis for evaluating Vision Zero and other safety projects.
Project Before/After Studies
Safety Surrogate Studies
A Safe System Approach is a proactive approach. Humans make mistakes and redundancy is key for no single mistake to lead to a serious injury or loss of life. Although crash analyses mean waiting 3 to 5 years for the appropriate sample size of data, the City can conduct before/after studies to determine the effectiveness and performance of new infrastructure in a much shorter timeframe. Crashes are one metric for evaluating success, but it is not the only way – there are several indicators of potentially severe crashes that the City can use to assess safety on the road network.
Safety surrogates, or factors that indicate the potential for a crash such as near misses, can be measured by observational studies, video analytics, and machine learning algorithms. These surrogates detect situations that could potentially lead to severe crashes, even if these situations did not result in a crash at the time. Analyzing safety surrogates can be used to examine crash contributing factors, such as speeding and red light running, and evaluate the efficacy of treatments that target and address these and other conflict points. These analyses provide important information to deploy the lessons from safety interventions throughout the entire City.
Reporting MetricsBefore/After studies of safety surrogates can focus on a host KPIs. The following metrics will help the City of Atlanta demonstrate project effectiveness without relying on crash data alone. Time-To-Collision (TTC) is the time remaining before the paths of two crossing road users would intersect (and a crash would occur) if their directions and speeds are maintained. Smaller TTC values indicate a collision is more imminent between two road users, while larger values indicate that there is more opportunity for one or both users to alter their paths and/or speeds to avoid a collision. Larger TTC values can indicate that the location is experiencing fewer close calls. Post-Encroachment Time (PET) is the time from when one road user leaves a specific location (or conflict point) to the time another user arrives at that same location. Smaller PET values indicate a higher likelihood for a collision, and an increase in average PETs can indicate that the location is experiencing fewer close calls. Red Light Running is assessed by instances of vehicles entering the intersection despite not having a permissive green or yellow light. Fewer instances of red light running may indicate fewer conflicts that may result in a severe crash. Crossing on Opposing Green is assessed by instances of pedestrians crossing the street without a green light or walk signal. It may indicate that signal times need to be adjusted so pedestrians can cross in an efficient manner and do not feel compelled to risk crossing against the signal. Typical Speeds are captured and instances of speeds 10 mph over the speed limit are evaluated. Average speeds are also calculated. Slower speeds increase potential reaction time for drivers, as well as reduce the force of impact if a crash occurs. Counts of Vehicles, Pedestrians, and Cyclists are captured as they enter a conflict zone (e.g., intersection). Counts of users at an intersection, intersection approach, or midblock section of road provide important information on exposure and data for normalizing the results.
Data Collection and AnalysisVideo assessments are conducted at each location. They can last 24-72 hours depending on the circumstances at each location. The extended timeframe allows the City to capture operations at the peak times and days, as well as periods of lower activity. A proprietary algorithm detects potential conflicts and safety issues, capturing data for to calculate the KPIs. The City can also capture road user counts at each location (such as vehicles, pedestrians, and cyclists) to demonstrate project usage. A safer system encourages a more efficient and active road network, and these before/after evaluations can help show that safer infrastructure benefits everyone.
Recent Project Evaluations
Campbellton Road and Willis Mill Road
10th Street and Monroe Drive
Video analytics and before/after studies can help demonstrate changes in conflicts between road users and the effect of interventions on the potential for fatalities and serious injuries. View examples of these conflicts and near misses.