[Phil_Cutcliffe]

Here is an example for you..

Код:

public OnPlayerStateChange(playerid, newstate, oldstate)
{
	new vehicle = GetPlayerVehicleID(playerid);
    if(newstate == PLAYER_STATE_DRIVER)
	{
	    if(GetVehicleModel(vehicle) == modelnumberhere)
	    {
	        SendClientMessage(playerid, COLOR_WHITE "Your message here");
			return 1;
	    }

EDIT:

Please note: Like the guy said above.. This will make it so anyone who enters ANY VEHICLE with ONLY THIS MODEL NUMBER will get the message. For example if you set the model number to 900 and the vehicle was a jeep.. Everyone who enters any jeep will get the message.

+Rep me if I helped you