"Safety is this department's top priority," LaHood said Wednesday in a release. "These new and updated standards will help make our nation's roads and bridges safer for drivers, construction workers and pedestrians alike."
The manual is the standard for all traffic control devices, including traffic signs, pavement markings, signals and other devices used to regulate, warn or guide traffic, LaHood said. Uniformity in all aspects of signage and signals helps reduce crashes and traffic congestion, he said.
The 2009 manual features new and updated requirements, ranging from changes in highway signs and bike lanes to the color of high-visibility garments worn by road workers.
While most changes came from research, LaHood said, seven changes were recommended by the National Transportation Safety Board, representing the largest number of NTSB recommendations adopted at one time.
The new provisions include:
-- Replacing highway signs with brighter, larger and more legible ones that are easier to understand at freeway speeds.
-- Adding different lane markings for lanes not continuing beyond an intersection or interchange to give drivers more warning that they need to switch lanes if they don't intend to turn.
-- Changing the formula used to calculate crosswalk times to give walkers more time.
-- Identifying electronic toll collection lanes with purple signs -- the first time purple has been sanctioned for use on highway signs.