you could do it like that, in order to make it more ralistic:
_civ = this select 0
_veh = this select 1
#aLoop
!(player distance _civ < 50) : goto "run"
goto "aLoop"
#run
_civ doMove getpos _veh
#bLoop
!(_civ distance _veh < 2) : goto "Mount"
goto "bLoop"
#Mount
player action ["get in",_veh]
#Chase
_pos = getPos player
_civ doMove getPos player
?(_civ distance player) > 100 : goTo "abort"
~0.001
goto "Chase"
"Abort"
?(_civ distance player) < 50 : goTo "chase"
goTo "abort"
exit
the trigger is the same but this script will actually cause the civ to run to the vehicle, get in and follow you, if the distance between the civ and you gains a higher value than 100, the civ will stop moving. if player moves within 50m to civ, civ will restart the chase.