Quantifying the value of corridor retiming in New Jersey

To understand the impact of corridor retiming along an important stretch of the High Street/Mount Holly Bypass, the Delaware Valley Regional Planning Commission (DVRPC), in cooperation with Burlington County and New Jersey Department of Transportation, asked Imperial Traffic & Data Collection to perform a before-and-after analysis.


Using Miovision Scout and the DataLink platform to collect and analyze traffic data, including travel times, Imperial Traffic & Data Collection was able to clearly show that signal retiming at 19 intersections along this important 5.5-mile stretch delivered positive results, including:

  • A 14% decrease in corridor median travel time for all movements (with a 25% decrease in Northbound travel time during the evening rush hour)
  • An estimated reduction of 154,850 gallons per year of fuel consumption and a corresponding reduction of 3,000 tons per year of CO2 emissions
  • An estimated user cost savings of $387,888 per year

Using the before-and-after travel time data collected from our study, we observed that corridor median travel time decreased by 14% for all movements, which helped Burlington County to quantify the annual savings of gallons of fuel, CO2 emissions, and end-user costs.— Lindsey Klein, CEO Imperial Traffic & Data Collection

Overcoming traditional challenges

Measuring the real-world impact of corridor retiming is notoriously difficult. Without hard data to show the benefits and to enable calculations of the financial returns, the reality is that retiming projects aren’t performed as frequently as they should be.

Quantitative evaluations, like the studies available through Miovision DataLink, make it possible for traffic engineers to demonstrate before-and-after impact. These data visualizations and reports also make it easy for cities to show that they’re putting taxpayer funds to very effective use.

Collecting reliable real-world data

Vehicle travel time is a key input to impact assessments. To gather this data in the field, Imperial Traffic & Data Collection relied on Miovision Scout, which senses the unique (and anonymous) MAC address of passing mobile devices. By collecting this information during the multiple two-hour measurement periods, engineers could get a reliable picture of commuter habits during peak traffic periods.

The Scout units also collected video that Miovision DataLink analyzed to produce multimodal turning movement counts along the length of the corridor. This rich data allowed Imperial Traffic & Data Collection to examine changes in travel patterns, including any induced demand that might result from the corridor becoming a more attractive commuting route.

Using before-and-after analysis to show positive return

By comparing “before” data gathered in November 2017 and “after” data gathered in November 2018, Imperial Traffic & Data Collection was able to clearly show the significant positive impact from the corridor retiming project.

Travel-time measurements and turning movement counts revealed major improvements in bidirectional point-to-point travel time during commuting periods:

  • Median corridor travel time for all movements improved by 14%
  • Southbound travel time dropped by approximately 10%
  • Northbound travel time declined by as much 25.6%
  • The number of stops in a run decreased by roughly 50% during weekday peak hours

While commuters no doubt enjoy the faster, less-interrupted journeys, the second-order benefits are also impressive, including:

  • An estimated reduction of 154,850 gallons/year of fuel consumption
  • A corresponding reduction of 3,000 tons/year of CO2 emissions
  • An estimated user cost savings of $387,888/year