On Not Having an Impact

Jan. 1, 2006

Over 40,000 people per year are killed in highway incidents in the U.S. It is a staggering number—enough people to fill at least one football stadium—but maybe not as shocking as the sudden rise in highway fatalities in the early days of motor vehicles.

Highway fatalities soared from 10,723 in 1918 to 31,215 in 1929.

Over 40,000 people per year are killed in highway incidents in the U.S. It is a staggering number—enough people to fill at least one football stadium—but maybe not as shocking as the sudden rise in highway fatalities in the early days of motor vehicles.

Highway fatalities soared from 10,723 in 1918 to 31,215 in 1929.

The very first person killed in a motor vehicle collision was Mary Ward, a scientist from Ireland, who was thrown from an experimental steam car and run over by the car on Aug. 31, 1869. Henry Hale Bliss was the first person killed in a car accident in the U.S. He was exiting from a streetcar in New York City. He turned to help a woman out of the trolley when an electric-powered taxicab struck him. The collision reportedly crushed his head and chest, and he died the next morning.

City engineers in the large cities scrambled to reduce congestion and collisions in those early years. Safety improvements sometimes came from unexpected directions.

Roads & Bridges was started in 1906 to document those events. In honor of our 100th anniversary, we take a look back at the past century of highway safety. Much of the research for this article came from America’s Highways: 1776-1976, an excellent book compiled by the Federal Highway Administration.

The engineers found that one of the most effective ways of reducing the danger on city streets was to cut back the cornering radius of curbs at intersections from the typical 4 or 5 ft to a radius of 12-15 ft. The extra room allowed vehicles to turn right without swinging wide into the adjacent lane, improving traffic flow.

Other actions that eased congestion and increased safety included one-way streets, automatic traffic signals and stop signs, which were at that time a relatively new innovation.

Even before automobiles became ubiquitous, William Phelps Eno was thinking about traffic safety—horse-drawn carriage traffic. Eno wrote a traffic plan for his hometown of New York in 1903. The plan codified rules for driving, pavement markings, signs, driver hand signals, driver licensing and speed limits. He also designed automobile traffic plans for New York, London and Paris.

Eno founded the Eno Foundation for Highway Traffic Control in 1921 and in 1926 published the landmark book Fundamentals of Highway Traffic Regulation.

Highway fatalities were such a national crisis that Secretary of Commerce Herbert Hoover summoned highway and safety experts from all over the country to the First National Conference on Street and Highway Safety in December 1924 in Washington, D.C. What the group found was a hodgepodge of state and city traffic regulations.

Off with their crowns

The Committee on Traffic Control, one of several committees formed by Hoover before the conference, reported that one hazard on the roads was the high crown left on many roads from the days of horse-drawn vehicles. The high crown encouraged drivers of autos to ride near the center of the road and dangerously close to oncoming traffic.

Reducing high crowns was one of the recommendations of the Committee on Construction and Engineering. The construction committee made a slew of recommendations, including putting off-road stopping places on rural highways; reduce grades to just 6% or less on primary highways but up to 9% in the mountains; main highways should have a minimum curve radius of 300 ft and a minimum sight distance of 300 ft. Crashes at railroad-grade crossings accounted for 10% of all highway fatalities in 1924, and they remain a problem to this day.

The country’s most urgent safety problem, the Committee on the Motor Vehicle concluded, was the design of headlights that would light the road ahead without blinding drivers of oncoming vehicles.

The solution to one particular problem of 1924 seems obvious and taken for granted now: the windshield wiper. There was a time when windshield wipers were not standard equipment. The Committee on the Motor Vehicle wrote, “Some device for cleaning the windshield from rain and snow, that can be conveniently operated by the driver should be available.”

Also in 1924, the stop sign changed colors from black letters on a white background to black on yellow.

The American Association of State Highway Officials (AASHO) in 1924 adopted standard shapes and colors for highway signs, including yellow for caution signs and red for stop signs. AASHO published the first Uniform Manual for Highway Signs in 1927. The manual contained the familiar black-and-white shield designating U.S. highway routes.

It may be difficult for many people alive today to imagine a stop sign as anything but a red octagon, but until 1955 the stop sign was black on yellow. The Manual on Uniform Traffic Control Devices for Streets and Highways of 1955 changed the colors to white on red in response to research that showed drivers observed the red sign more effectively.

The Bureau of Public Roads (BPR) began its studies of the visibility and legibility of various sign colors in 1933.

AASHO combined with the National Conference on Street and Highway Safety in 1935 to form the Joint Committee on Uniform Traffic Control Devices, which produced the first Manual on Uniform Traffic Control Devices for Streets and Highways.

The very first stop sign was erected in Detroit in 1915. It had black lettering on a white background. One advantage of the unique, octagonal shape selected by AASHO was that it could be identified even from the back and distinguished from other traffic signs. Today, the white-on-red, octagonal stop sign is used in countries around the world. The prevailing theory of road building in the 1920s was that highways should be laid in straight lines. Straight highways were thought to be safer because they demanded less effort from the driver. Straight highways also would accommodate the faster automobile speeds the designers anticipated in the future. Later research and experience revealed that the straight-highway theory had no more validity than the sun-revolves-around-the-Earth theory.

Gathering data

A stumbling block to even discussing highway hazards was the lack of crash statistics. Many states did not have a systematic method of recording complete and accurate traffic-crash data. Twenty states did not require collection of any crash data at all.

The second conference, called by Hoover in March 1926, approved a Uniform Vehicle Code that codified the best features of the various state laws concerning registration of vehicles, titling of vehicles, licensing of drivers and operation of vehicles on the highways.

A committee of the second conference assigned to study the causes of traffic crashes came to the conclusion that determining the causes of such accidents was going to be far more difficult than they initially thought. The problem warranted scrutiny by a permanent, national research organization. As a result, in 1927 the Highway Research Board formed the Committee on Causes and Prevention of Highway Accidents.

Congress responded in its own way to the growing highway fatalities. It appropriated hundreds of millions of dollars in grants to the states for highway safety programs during the 1930s and early ’40s.

It was research during the 1940s that confirmed the effectiveness of centerline marking on two-lane, two-way roads. Studies showed that a centerline was effective at keeping vehicles in the correct position and not encroaching on the left side of the roadway.

The benefits of a centerline were obvious to some people much earlier. Credit for being the first to have the idea of painting a line down the center of the road is a subject of debate. The California Department of Transportation gives the credit to Dr. June McCarroll of Indio, Calif., who was run off the road by a truck in 1917. That was when she got the idea to separate traffic with a centerline. She brought her idea to the local chamber of commerce and the local county board, but could not convince them. She launched a campaign with the Women’s Clubs of the state and eventually won acceptance but not before she took it upon herself to paint a line down the middle of U.S. 99.

Some sources give credit to Edward N. Hines, a charter member of the Wayne County (Mich.) Road Commission. Hines made many contributions to highway development in Michigan. The story in Wikipedia is that he got the idea of painting stripes to separate lanes of traffic in 1911 “after riding behind a milk truck that leaked milk onto the center of the road, leaving a stripe.”

The first divided highway was constructed in 1929 by Milwaukee County, Wis., as a way to improve safety. The county rebuilt part of Blue Mound Road with a gap of “neutral ground” separating the opposing lanes of traffic. After the split, the county found that the highway could carry more traffic at higher speed than before.

Despite their success, divided highways were slow to catch on; only 1,200 miles of nonurban divided highway had been built by 1937.

Controlling access added another level of safety for motorists by eliminating places where drivers had to worry about receiving a rude surprise from another vehicle entering the roadway before accelerating up to speed.

After the early 1940s, with the basic concepts and principles of highway design and construction set, advances in safe design of highways were mostly refinements.

Vehicle widths have stayed about the same since 1944 and so has the standard lane width. In 1944, the BPR released a report concluding that 12 ft was the best lane width for the safety and comfort of travelers. The guideline was soon adopted by AASHO as a standard for primary highways.

As a result of all the research into highway safety, starting in the 1930s and ’40s, older roads, even roads that had healthy pavement, were deemed obsolete because of their design. Curves were too sharp for then-current speeds. Sight distances were too short for passing. Road pavements and shoulders were too narrow. Finally, some older roads were simply not designed for the quantity of traffic that was trying to use them.

Replacing these obsolete roads became a major program.

Tune in next time...

Next month, “100 Years of Highway Safety” will conclude, focusing on events during the second half of the 20th century and the past hundred years of developments in traffic management, including traffic-control devices and technology.

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