Chū le chēhuò děi xiān dǎ diànhuà gěi jiāojǐngduì.
After an accident you should first call the traffic police unit.
Tips
usage
交警队 is the local squad; 交警 alone is the general term for 'traffic cop.' 交警大队 is the next level up (district-wide). You'll also hear 车管所 for the vehicle-registration office - different agency.
