I write in response to the June 3 front-page story "Truck Crash Paralyzes Area Roads: Rig With Explosives Flips Off Ramp at Springfield's Busy `Mixing Bowl.' "

All engineers except those who work for the Virginia highway department -- especially the ones who designed the Springfield Interchange of I-95, I-495 and I-395 -- know from Static and Dynamics 101 that when you turn, you develop centrifugal force. This centrifugal force can destabilize you unless counter (centripetal) force is provided.

For trains and motor vehicles, it is the responsibility of the engineers to design the road in a way that takes centripetal force into account so that the trains or automobiles do not overturn. Trucks that have a higher center of gravity than passenger automobiles are more prone to being overturned by centrifugal force. Jeeps and SUVs overturn more easily for this reason.

The truck carrying the explosives overturned because the driver, at 4 a.m., found that stretch of I-95 empty and maintained the legal road speed (55 mph or higher) that she had been accustomed to driving so long. She did not know that I-95 at that spot has a design defect -- no banking is provided.

This truck was not the first to overturn at the spot. A look at the records of overturned trucks on all of I-95 will show a glaring example of a design defect at that particular spot of Springfield's "mixing bowl." Large numbers of trucks have overturned there.

MOZHARUL HOQUE

Springfield

Experts are reflecting on the deplorable response to the semi truck spill in Springfield with plenty of accusations to go around.

Fairfax County had primary jurisdiction, and armchair experts seemed to have hurled their strongest criticisms at them. But alternative routes were clogged at best and nonexistent at worst. What can you expect when the Fairfax County Parkway begins near some guy's garage in Reston and ends near I-95? You can see where you want to go, but you can't get there. Everyone agreed that clearing the mess took too long. Keep in mind, the county has hundreds of its staff preparing for the Fairfax Fair. There are priorities, you know.

Virginia had secondary responsibility, but the governor is focused on other issues. For example, I really partied this year with the huge rebate I got on my personal property tax, and he's working to make that rebate even better. There is no truth to the rumor that this accident was staged so that people would stop complaining about the everyday traffic snarls at the Springfield exchange.

Moving up the food chain to the federal level: The National Transportation Safety Board is investigating this accident. I am not sure what it does except file reports, but I am sure we need more reports. Doesn't black powder come under the jurisdiction of the Bureau of Alcohol, Tobacco and Firearms?

Our Northern Virginia roads are horrible. They have been and, with all this development, they will continue to be. Everybody lets developers in, but no one makes the transportation system keep pace. Springfield, the Dulles Corridor, Tysons Corner and Crystal City: Does any area have a satisfactory transportation network?

The only hope I see is to pass a law that politicians from the president down no longer are to have access to helicopters, limos or drivers -- they must all be issued Ford Escorts with no air conditioning. If they get stuck often enough, some changes will be made.

ALAN ROTHSTEIN

Herndon