Speeding is a leading cause of accidents on Interstate 70 between the Missouri River and the St. Louis city limits, but driver inattention, unsafe lane changes and tailgating are major contributors as well.

A month-old speed crackdown by some north St. Louis County municipalities has touched off a debate about whether speeding on the highway is a real problem — or just an excuse to post more cameras on interstates.

A Post-Dispatch review of vehicle crash summaries compiled by the Missouri Highway Patrol found that speeding contributed to 31 percent of the 4,969 accidents on that segment of I-70 from 2005 to 2009. By contrast, speeding contributed to 19 percent of highway and interstate accidents across Missouri.

Inattention contributed to 22 percent of accidents on the stretch of I-70, followed by improper lane use, at 21 percent, and following too closely, at 19 percent. The newspaper also found that:

• The vast majority of accidents — about 71 percent — resulted in property damage but no injuries. That is roughly equal to the statewide average for highway accidents during the same five-year period.

• Accidents rose sharply in 2008 and 2009, when I-70 served as a major detour for motorists displaced by the reconstruction of Highway 40 (Interstate 64). Statewide, total highway accidents tapered off during that period.

• Speed was a factor in 10 of the 19 fatal accidents on I-70 since January 2005, but alcohol or drug impairment contributed to 10 accidents in which someone was killed.

Under the state crash-reporting guidelines, accidents can have more than one contributing circumstance.

The Post-Dispatch sought the crash summary reports after eight cities along that segment of highway through north St. Louis County formed an "Accident Reduction Corridor" and vowed to crack down on speeders.

Some law enforcement officials have expressed concerns that the alliance of police agencies is a prelude to installing speed cameras on the highway. St. Louis County refused to participate after learning that an early organizing meeting for the I-70 group was in a room paid for by a local speed-camera company.

Missouri Highway Patrol Capt. Ronald Johnson, commander of Troop C in the St. Louis area, said he didn't see anything dramatically out of the norm when he looked at accidents and calls for service in the I-70 corridor.

"If you look at the number of accidents, the severity of accidents and the time of day, you are not going to see a lot," Johnson said. "You will probably see an increase in those numbers as you get further east of (Interstate) 170 on 70 ... because that traffic begins to get more congested" as the highway approaches downtown St. Louis.

Johnson recalled how accident rates on Highway 21 — known widely as a "Blood Alley" for years — required extra attention. So did northbound Interstate 270, just south of I-70, before double white lines were painted to prevent people from darting into traffic and triggering rear-end accidents.

But St. Ann Police Chief Robert Schrader said speeding was a significant problem on I-70, and his officers have written 500 to 600 tickets while focusing on those driving 15 mph or more above the 55 mph posted speed.

"The people on Highway 70 are out of control — the violators, that is," Schrader said. "It is unbelievable the way people are driving. It is one right after another."

Said Pine Lawn Police Chief Rickey Collins: "I don't think people will ever slow down. My professional opinion is that people will always speed on highways because they feel it will never happen to them until what? It happens to them or a family member."

Collins, whose department is one of the eight agencies cracking down on I-70 speeding, said there were too many accidents in which speeding drivers lose control of their vehicles near Jennings Station Road.

Because there is no state statute covering accident reduction corridors, Schrader said, the agencies are working to make the seven-mile stretch they patrol a Travel Safe Zone. Fines could then be doubled for speeding.

Schrader said he believed the percentage of accidents in which speeding plays a role was actually higher than 30 percent. While acknowledging that there are other common causes of interstate accidents, Schrader said speeding was one driver behavior police can attempt to control.

Schrader said the police cooperative was not a "money grab," as evidenced by the fact that his officers are targeting only speeders traveling faster than 70 mph. But, once again, Schrader said he would not rule out the use of speed cameras on I-70 in the future. "I am not ruling out any future technology for Highway 70," he said.

St. Louis County Police Chief Tim Fitch said that did not surprise him.

"At the beginning," he said, "this was an initiative to have a legitimate excuse to have speed cameras out there."

In a letter to state Rep. Steven Tilley, R-Perryville, Fitch said none of the agencies that had rolled out speed cameras had been able to demonstrate that photo enforcement is necessary to reduce speed-related crashes.

"Absent those statistics, one can only assume the cameras are being placed to enhance revenue for these communities," he wrote. "As an example, Charlack initially placed a camera on northbound Interstate 170. Their tiny stretch of this highway takes only seconds to pass through."

Fitch is asking the Missouri House of Representatives to limit the use of speed cameras.

Photo enforcement, he said, should be deployed only with the permission of the Missouri Department of Transportation, and only when traffic crash data "indicates the primary cause of accidents to be speed related or in work construction zones."

Proceeds should be distributed to schools in the county where the violation took place, he added. And speed cameras should identify the driver of the car, and points should be assessed by the state Revenue Department.

Johnson, the Highway Patrol commander, said camera-generated tickets also left out an important ingredient to changing driver behavior: education.

An officer who pulls over a speeding motorist has a chance to talk to that driver about the danger of traveling at unsafe speeds, Johnson said. That is missing with the speed cameras.

"Traffic enforcement is about education," he said. "It is not about giving out a ticket. If someone has the money to pay the ticket, it won't change the behavior."