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Center for Advancing Research in Transportation Emissions, Energy, and Health (CARTEEH)

A USDOT University Transportation Center

Traffic Flow Starts and Stops (Acceleration and Deceleration)

Traffic flow examines how vehicles, motorists, and infrastructure interact to better comprehend and design a road network that moves traffic efficiently and has fewer congestion issues.1 This explains how motorists stop their vehicle while observing the traffic signal and start it again to proceed. However, the start and stop of traffic flow depends on the movement of vehicles along the lane and how they interact with other vehicles, pedestrians and bicyclists, and traffic lights. Numerous other criteria like design speed, the proportion of heavy vehicles, the number of lanes, and the junctions on the road impact this.2 Traffic flow measurement is an essential metric to indicate the effectiveness of different strategies to reduce vehicle emissions.

This indicator helps determine the effectiveness of the following objectives

  • Less Contamination
  • Less Emissions
  • Less Traffic Noise
  • Connectivity and Inclusion
  • Healthy Destinations
  • Less Traffic Violence
  • Active Transportation
  • Green Space

Data Collection

The main source of real-time traffic data is Google Maps. The Google Maps website compiles live traffic data and offers a way to monitor the flow of traffic.3 Additionally, the TomTom Traffic Stats provides direct access to the biggest historical traffic database. It is possible to detect traffic flow, evaluate the effects of modifications to the road network, and enhance traffic management with detailed insight into the road speeds, travel durations, and traffic density utilizing various data sources.4

Examples

U.S. Department of Transportation Study on Traffic Flow

The U.S. Department of Transportation conducted a study to measure the rate of traffic flow in the United States. According to USDOT, the average rate of traffic flow was calculated to be about 50 miles per hour. However, there are many factors that can affect this rate, including the time of day, the type of road, and the weather conditions. USDOT officials used a variety of methods to measure the rate of traffic flow. They looked at the number of cars on the roads, the amount of time it took for cars to travel certain distances, and the average speed of cars. They also looked at how often accidents occurred and how long it took for emergency vehicles to respond to them.

https://www.transportation.gov

1. Research Tony Harper, Hannon K. What does traffic flow mean? [Internet]. Definitions.net. [cited 2022 Jul 13]. Available from: https://www.definitions.net/definition/traffic%20flow
2. Chegg.com. [cited 2022 Jul 13]. Available from: https://www.chegg.com/homework-help/definitions/traffic-flow-8
3. Makvana, M. How to check traffic in Google Maps [Internet]. How-To Geek. 2022 [cited 2022 Jul 29]. Available from: https://www.howtogeek.com/781987/how-to-check-traffic-in-google-maps/
4. Traffic stats [Internet]. TomTom. [cited 2022 Jul 29]. Available from: https://www.tomtom.com/products/traffic-stats/