Here's a script that I've made but the problem is that everyone can enter the vehicles not only FBI
fbi1 = createVehicle ( 596, -2429.7998046875, 515.2998046875, 29.700000762939, 0, 0, 215.99670410156 )
fbi2 = createVehicle ( 596, -2425.69921875, 518.5, 29.700000762939, 0, 0, 221.99523925781 )
fbi3 = createVehicle ( 596, -2422.3994140625, 521.599609375, 29.700000762939, 0, 0, 225 )
function lockfbi(player, seat, jacked)
if (source == fbi1 and source == fbi2 and source == fbi3) then
local skin = getElementModel (thePlayer)
if ( skin == 100 or skin == 255) then return end
cancelEvent()
outputChatBox ( "Only FBI can enter this vehicle", player, 0, 0, 150, true )
end
end
addEventHandler ( "onVehicleStartEnter", getRootElement(), lockfbi )