scope:

ITE prepared this recommended practice to reflect the current state-of-the-practice and provide the user with a broad overview of key considerations for vertical deflection measures as speed reduction techniques including speed humps, speed tables, raised pedestrian crossings, raised intersections, and traffic calming roundabouts.

While an earlier ITE recommended practice focused on speed humps and speed tables, this new recommended practice expands the discussion to be more inclusive of intersection as well as mid-block techniques. Over the past decade as more measures have been installed and more data regarding effectiveness (both positive and negative) have been collected, refinements have emerged, including:

• Replacing transverse humps with a cushion design to better address all road users

• Greater quantitative understanding of speeding and volume problems

• Defining safety-related speed metrics (percentages of vehicles traveling 5 and 10 mph above proper speed limits)

• Improved data collection of speed distribution to include 2 mph bins

• Uniform pavement markings

• More before and after study data regarding understanding of performance relative to speed and volume

• Documentation of legal case studies and issues of liability

• Understanding of property value, noise, air quality, pavement impact and wheelbase of vehicles

This recommended practice was written primarily for engineers and planners working for public agencies to guide planning, public engagement and applications of speed reduction techniques.