Controlling the speed of a car.

How do I control the speed of prop_vehicle_jeep?
Specifically, I’d like to implement a cruise control.

[lua]
hook.Add(“Think”, “CruiseControl”, function()
local vehicle = Entity(2) – get your vehicle somehow
if !IsValid(vehicle) then return end

local delta = CurTime()%1/1000
vehicle:Fire("throttle", 30 + delta, 0)

end)
[/lua]