The speed limit will soon be changing on Loop 1604...changing often.

  Loop 1604 between 281 and I-10 is one of three highways in the state which will experiment with what is called a 'variable speed limit,' a speed limit which changes due to weather conditions or congestion on the highway.

  TxDOT's Laura Lopez says electronic signs along the road, which now flash messages about missing children or warn you that parking is not allowed at the Alamodome will notify motorists of a reduction in speed limit due to the conditions ahead.

  "The speed limit is 70 miles per hour, the signs will start to decrease as traffic is approaching, say, an accident," Lopez said.

  The idea, she says, is to prevent crashes that result from motorists driving too fast into a congestion scene, or weaving in and out of traffic, or even driving on the shoulder, trying to get around a backup.

  "It is used in other states, and it is shown to help reduce rear-end collisions," she said.

  Lopez says the speed will gradually decrease as motorists get closer to the wreck, or will decrease and stay low in case of, for example, ice, fog, or heavy rain which makes driving hazardous.  When the condition that caused the lower speed is done, the speed will revert to 70 mph.

  "They will be in five mile increments, so as traffic is coming to an area where there is congestion, the speed limits will begin to reduce."

  But one challenge is facing the variable speed plan...whether police can write tickets for violating 'variable speed' restrictions.  Currently, state law allows police to write motorists tickets for violating 'posted' speed limits, which has generally been interpreted to mean the speed limit posted on permanent signs along the highway. 

  An Attorney General's opinion or even an act of the Legislature may be needed to allow enforcement of speed limits which are, in the words of one lawyer, 'temporary and arbitrary.'

  The other places where 'variable speed limits' are being tested are in Waco and Brownwood.

  The test will begin later this month and last throughout the summer.