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Articles - November, 1997
November 1, 1997Survey Investigates the Relationships Among Design Speeds, Operating Speeds, and Posted Speed Limits
November 1, 1997
November 1, 1997
November 1, 1997
Since the 1930's, design speed has been a primary factor in selecting the vertical and
horizontal alignments of U.S. roadways. Since about the same time, posted speed
limits have been based on a statistical analysis of individual vehicular speeds observed
on the roadway. The speed limit is set at the 85th percentile speed--that is, the speed
below which 85 percent of motorists travel. As a result, motorists often travel legally at
speeds greater than the roadway's design speed. The Texas Department of
Transportation (TxDOT) conducted a nationwide study to identify problems with the
relationships among design speeds, operating speeds, and posted speed limits and to
solicit possible solutions to those problems. Kay Fitzpatrick, Brian Shamburger, and
Dan Fambro documented the results in the article summarized here, "Design Speed,
Operating Speed, and Posted Speed Survey."
City in New York Found Not Liable for Motorist's Fall in Municipal Parking Lot
A woman fell in a municipal parking lot and sued the city of New Rochelle, New York for
the lot's uneven surface. The Supreme Court of Westchester County granted the city's
request for a summary judgment and dismissal of the suit. On appeal, the Supreme
Court, Appellate Division, ruled that the parking lot qualified as a highway; therefore,
since the city had not received previous notice of the condition, it could not be held
liable for the woman's injuries.
State of Washington's Recreational Use Immunity Statute Upheld in Pedestrian's
Death
A seven-year-old pedestrian died after being struck by a vehicle on a bridge
designated as a scenic overlook. When the child's father sued, the Superior Court of
Whatcom County granted Washington State's motion for summary judgment. The
Court of Appeals of Washington, Division 1 confirmed that a recreational use immunity
statute covered the bridge. The appellate court concluded the dangers of the bridge
were obvious rather than latent conditions and did not qualify as exceptions to the
statute.
The Effect of Decreases in Vehicle Weight on Injury Crash Rates by Ellen Hertz,
Ph.D.
This is a reprint of a January 1997 "Research Note" from the U.S. Department of
Transportation's National Highway Traffic Safety Administration (NHTSA). It
summarizes Ellen Hertz' research report entitled "The Effect of Decreases in Vehicle
Weight on Injury Crash Rates." NHTSA's National Center for Statistics and Analysis
recently completed an analysis to estimate the effect of a one hundred (100) pound
reduction in the average weight of passenger vehicles on the per crash rates of
incapacitating injury to drivers. In the analysis described here, three "scenarios" were
considered: (1) the effect of a hypothetical 100 pound reduction on light trucks and
vans (LTVs), with the weight of passenger cars (PCS) unchanged; (2) the effect of a
hypothetical 100 pound reduction on PCS, with the weight of LTVs unchanged; and (3)
the effect of a hypothetical 100 pound reduction on all passenger vehicles.
negligence, appeals, highway, traffic, expert.
Edge drop, accident, collision, crash, edgedropoff, road construction, signs, signals, traffic control devices.
Accident Investigation, Expert Witness, Injury Litigation, Liability, Court, Roy Anderson, Transportation, National, Travel, law, legal, federal highways, road construction.