(Apologies is this doesn't read well, I'm terribly underslept after weeks of this)

Tl;Dr Loud cars doing laps all night in small Aussie town. Looking for ways to spook them or have them damage their own cars.

I live in a regional town in Queensland, Australia and just before fuel prices rose, there was an uptick in obnoxiously loud cars and bikes doing laps around town. Inexplicably, they have only become worse. Last night, they were so loud I ended up calling the police around midnight. I was told I wasn't the only one who had called. They didn't ease until after 2am, though it sounded like maybe one or two had left the group earlier than 'normal'. Not sure if the police were successful.

They do this every night, from 9pm through til 4am sometimes. At least one of the cars backfires constantly which echoes and is impossible to ignore. Apparently the car (at least the noise) is known across town and it's been like that for more than a year.

I'm planning to call the non-emergency police line during the day to make a noise complaint. I'm positive I won't be the first in town to have done so.

I lay there, trying to sleep, thinking of 'spilling' something slippery on the road, caltrops... last night I thought of setting up a silhouette of a running person near the side of the road between their laps to spook them...

We live near a racecourse (for horses, but empty at night) so there would be a good opportunity to have them veer off into that without anyone getting hurt (other than them). The town would be livid if they damaged their favourite drinking and yelling at horses place.

Any thoughts, commiserations or suggestions welcomed. Bonus points if its something ephemeral