The Texas Department of Transportation is issuing a traffic safety advisory for the people driving along Interstate 35 because state troopers have seen illegal and dangerous traffic activities by many drivers on the highway’s southbound lanes, the Laredo Morning Times reported.

It seems some purposely drive below the posted speed limit to lure others who seek special vehicle permits to enter Mexico. Once other drivers have joined the group of vehicles they travel to undisclosed locations for permit authorization, the paper reported.

Officials say vehicles impeding traffic are driving as low as 35 miles per hour in a 70 mph posted speed limit. The minimum allowable speed in a 70-mph speed zone is 60 mph.

It is against state law to impede traffic on state and U.S. highways in Texas, as it is illegal to drive on the shoulder of the road. Also, parking on the state right-of-way and parking on frontage (access) roads is prohibited.

Violations of these laws are considered a Class C misdemeanor and punishable with fines up to $500.