The Kansas City Scout program used ramp meters to improve traffic flow and reduce overall peak period travel times on a seven mile section of I-435 by 1 to 4 percent.

KC Scout ramp metering program on I-435

I-435 and Metcalf Ave,Kansas City,Missouri,United States

Summary Information

The Kansas Department of Transportation (KDOT) and Missouri Department of Transportation (MoDOT) implemented the Kansas City (KC) Scout ramp metering pilot program to improve safety and traffic flow on a seven mile section of I-435 between Metcalf Avenue and the Three Trails Memorial Crossing. A total of seven interchanges were equipped with ramp metering systems designed to regulate on-ramp traffic volumes in response to prevailing freeway traffic conditions and reduce sudden weaving and braking movements adjacent to on-ramps to smooth traffic flow and increase throughput and safety.


Travel time surveys were used to evaluate vehicle speeds and travel times on I-435 before and after ramp meters were installed. The before data were calculated in 2007 and the after data were collected in 2010, after ramp meters were operational for more than six months. Evaluators used the floating car method to determine average vehicle speeds during morning (6:00 AM to 8:00 AM) and afternoon (4:00 PM to 6:00 PM) peak periods in eastbound and westbound directions.


Speeds increased on several freeway segments and decreased on others. Most notable increases were observed on I-435 between the State Line Road and Wornall Road interchanges. The most notable decreases were observed in the eastbound direction during afternoon peak periods. Although some freeway segments experienced improved freeway speeds and others did not the net overall effect resulted in improved travel times after ramp meters were installed.
  • Overall, travel times along I-435 improved when ramp metering was added to the corridor. The improvement is the result of a net overall effect of some freeway segments that experienced faster freeway speeds combined with those that did not.
The FHWA Travel Time Index for I-435 decreased after ramp meters were installed indicating the ramp metering system contributed to less delay. The Travel Time Index is defined as the ratio of the average travel time over the free flow travel time for a section of freeway. The following table drawn from the source report compares Travel Time Indexes for eastbound and westbound sections of freeway during morning and afternoon peak periods before and after ramp meters were operational.

Study Area
Travel Time Index
Before Ramp Meters
Travel Time Index
After Ramp Meters
Percent Decrease
Morning PeakI-435 Westbound
I-435 Eastbound
Afternoon PeakI-435 Westbound
I-435 Eastbound

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Ramp Metering 2011 Evaluation Report

Author: Kansas City Scout Program

Published By: Kansas DOT and Missouri DOT

Source Date: 2012



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ramp meters

Benefit ID: 2012-00800