CCTV | DMS | HAR | RWIS | VSL | Dynamic Speed Displays | Ramp Meters| Curve Warning Systems| Intelligent Work Zones | ICWS

Planning Guidance for the Installation and Use of Technology Devices for Transportation Operations and Maintenance

ENTERPRISE Transportation Pooled Fund Study

DSDS Guideline 1 - Transition Zones

Purpose: To promote speed limit adherence in locations of speed limit reduction zones.

Engineering judgment should be used to assess potential implications that may result from installation of DSDS.  This planning guideline does not mandate the use of DSDS.

1. The 85th percentile speed (as determined by a speed study) at a location within the lower speed limit area exceeds the posted speed limit by at least 10 mph. (1)

AND

2. The zone experiences a posted speed limit reduction of at least 10 mph.

AND

3. There are no other Dynamic Speed Display Signs along the route encountering the speed transition, within 5 miles in either direction (excluding DSDS within school zones). (2)

Note: Signs tend to be most effective where there are two lanes or less in one direction of travel.

References:

(1) City of St. Paul Minnesota, Department of Public Works, Traffic Engineering. Dynamic Speed Display Signs . 2004.

(2) Mn/DOT. Dynamic Speed Display Sign Memo. http://dot.state.mn.us/trafficeng/committees/minutes/jul/Attachment%202.pdf.