STOP ARM HISTORY

According to the two founders of Specialty Manufacturing Co, Jim Wicker and Larry Burton, the school bus stop arm goes back about 70 years to a picture taken in Georgia. The picture shows a new Blue Bird bus built on a Model T Ford chassis, circa 1927-1930. The bus driver had a paddle that looked like a white-gloved cop hand (similar to the Keystone Cops) with the word STOP painted on the hand. When the driver stopped the bus to pick up students and let them off, he would stick the sign out the window. That was the precursor to today’s modern stop arms. (Note: Burton thought this picture had to be taken between 1927 and 1930. The Model T truck was produced only until 1927.)

A patent for the stop arm mechanism was filed in 1941 (Pat. No. 2243472). But the next definitive step evolved from an idea at the NC Dept of Transportation.

Someone there came up the concept of a rectangular piece of metal mounted on a door hinge with a handle to swing out the stop arm. A company called Power Brake Systems located on Morehead Street in Charlotte, N.C., developed this idea into the vacuum stop arm that was patented in 1960. (Note: Pat. No. 3313265.) According to Burton and Wicker, someone at Power Brake Systems developed the very first vacuum stop arm somewhere between 1958-1962 when Burton was a salesman with Sidney Butz & Assoc. An employee of Power Brake Systems figured out how to adapt the mechanism that operated the power brake system of an automobile, which has a rubber diaphragm. The developer adapted this concept to the stop sign so the driver did not have to pull a handle, but just had to pull a metal switch. They used a vacuum valve made of cast iron. There is some confusion about who exactly came up with the adaptation idea.

Carolina Metal Products in Charlotte, N.C. took over the stop arm production. The company was bought out by Pittsburgh Reflector in 1963. The stop arm was a very small part of this new business and deliveries were not being met. At that time about eight states were using the stop arm, and Burton thinks those eight may have had stop arm mandates.

At that time, Sidney Butz & Assoc, a manufacturers rep company in Charlotte, handled the Carolina Metal Products line. Butz got totally frustrated with Pittsburgh Reflector’s poor order fulfillment so he asked one of his salesmen, Larry Burton, to open a new business to make the stop arms and other metal fabrication products. Specialty Manufacturing Company (SMC) was born in 1963. Butz underwrote Burton and a partner named Robert Bullock to start SMC and make the vacuum stop arm, stop signs and other metal fabrication parts. Bullock had been an employee of Carolina Metal Products Co.

Jim Wicker joined SMC as a partner a couple of years later and the company developed the air stop arm. The vacuum and air stop arms carried the market for the next 15-20 years. In 1981, The Ellison Co. bought Specialty Manufacturing.

In 1987 or 1988 a man who worked with the school bus body system developed an electrically-operated stop arm. (Pat. No. 3741147. That should be under the name Joseph Latta and dated 1973.) Specialty was told about the electric unit and worked with the developer for several years. In the early 1990’s, SMC developed its own electrical design, the 5-series, and patented it, using the mechanism for both stop arms and crossing control arms.

As stop arms became more popular, regulations came into play. SAEJ1133 was written after the regulation writers requested a stop arm from SMC. SAEJ1133 was the precursor to FMVSS131, the federal regulation that required every state to use stop arms. FMVSS131 was finalized May 3, 1991. By 1991, 42 states had mandated stop arms.

Since then, SMC has developed and patented the technologically advanced 6-series solid state stop arm.

This article is reproduced from the March 2001 issue of School Transportation News. All rights reserved.