cl_seatseater.lua

local doors = {
  {"seat_dside_f", -1},
  {"seat_pside_f", 0},
  {"seat_dside_r", 1},
  {"seat_pside_r", 2}
}

function VehicleInFront(ped)
    local pos = GetEntityCoords(ped)
    local entityWorld = GetOffsetFromEntityInWorldCoords(ped, 0.0, 5.0, 0.0)
    local rayHandle = CastRayPointToPoint(pos.x, pos.y, pos.z, entityWorld.x, entityWorld.y, entityWorld.z, 10, ped, 0)
    local _, _, _, _, result = GetRaycastResult(rayHandle)
    return result
end

Citizen.CreateThread(function()
  while true do
    Citizen.Wait(0)
	local ped = GetPlayerPed(-1)
    if IsControlJustReleased(0, 23) and running ~= true and GetVehiclePedIsIn(ped, false) == 0 then
      local vehicle = VehicleInFront(ped)
      running = true
      if vehicle ~= nil then
        local plyCoords = GetEntityCoords(ped, false)
        local doorDistances = {}
        for k, door in pairs(doors) do
          local doorBone = GetEntityBoneIndexByName(vehicle, door[1])
          local doorPos = GetWorldPositionOfEntityBone(vehicle, doorBone)
          local distance = Vdist(plyCoords.x, plyCoords.y, plyCoords.z, doorPos.x, doorPos.y, doorPos.z)
          table.insert(doorDistances, distance)
        end
        local key, min = 1, doorDistances[1]
        for k, v in ipairs(doorDistances) do
          if doorDistances[k] < min then
            key, min = k, v
          end
        end
        TaskEnterVehicle(ped, vehicle, -1, doors[key][2], 1.5, 1, 0)
      end
      running = false
    end
  end
end)