FARGO (AP) - The attorney for a woman whose lawsuit led to reduced traffic fines in Fargo and other cities says the lawsuit is based on constitutional grounds.

Tim Purdon, who represents Stephanie Sauby of West Fargo, responded Wednesday to a motion filed by Fargo officials seeking to dismiss Sauby's federal lawsuit. The lawsuit alleges the Fargo fines violate Sauby's constitutional rights.

The state Supreme Court ruled in March that cities may not assess higher traffic fines than state law allows. Fargo, Grand Forks, Williston and other cities stopped the practice as a result.

Assistant Fargo City Attorney Stacey Tjon Bossart said earlier that despite the Supreme Court ruling, the city feels strongly that the higher fees do not rise to the level of a constitutional violation. She was not immediately available for comment Wednesday.

Purdon's response says charging illegal fees violates a person's rights to due process and equal protection under the constitution.

Two people could be driving 39 mph in a 35 mph zone in exactly the same location in Fargo, and the one cited by a city police officer would pay a larger fine than the one cited by a county deputy or state patrolman, he wrote.

"This distinction is arbitrary and has no rational basis or connection to the city's alleged purpose of traffic safety," he wrote.

Sauby was ticketed twice for speeding, twice for not wearing a seat belt, and once for failing to have her vehicle under control, court documents said.

A comparison of fines shows speeding up to 5 mph over the limit in Fargo costs $75 compared with a $5 state fine. Failure to have a vehicle under control brings a $100 fee in Fargo compared with a state fee of $30, court documents say.