Back to Expert-Tool Page > City--Population less than 50,000 > Reduce Congestion

Determine where and when congestion occurs. Then analyze why it occurs.

Speeds can be estimated from vehicle flows and densities. A number of surveillance devices are available for determining these. Some are portable and can be moved from place to place. Travel times can be measured by floating cars. Instrumented cars that automatically record travel times may be available on loan from a state highway department.

On arterials

• If there are delays at signalized intersections because the signals along the arterial are not coordinated, consider coordinating signals and optimizing cycles using a simulation program such as Transyt. If optimal cycles vary over the course of the day, consider using different timing plans at different times of day.
  
  
• If there are delays at signals because of left or right turns, consider a left turn pocket or right turn lane.
  
  
• If there is a delay at an isolated signal (nearest signal over 1 mile away), consider a traffic actuated signal that is green for arterial traffic except when actuated by a vehicle on the cross street.

Due to events or traffic surges

• Consider a combination of changes in signal timing to facilitate the movement of the traffic surges and variable message signs to route through traffic around the congested area. For periodic large events consider a portable traffic management center.

At rail crossings

• If there are delays at rail crossings and there is a grade-separated crossing nearby, consider using variable message signs to route vehicles to that crossing when a train is approaching or crossing.

Due to freeway traffic

• For backups at a freeway on-ramp, consider using variable message signs to divert travelers to other on-ramps, to channel freeway-bound traffic into one lane, and/or to divert non-freeway traffic around the backup.
  
  
• For large numbers of cars exiting the freeway, consider changing the signal timing to facilitate their movement away from the freeway and using variable message signs to divert other traffic around the congestion.

Due to incidents

• Consider using portable variable message signs and broadcast radio, if available, to divert people away from the incident site.