/******************************/
   ENGINES.H
/******************************/
/**
 * Writes the properties of a road vehicle into the RoadVehicleInfo struct.
 * @see RoadVehicleInfo
 * @param a image_index
 * @param b cost_factor
 * @param c running_cost
 * @param d sound effect
 * @param e max_speed (1 unit = 1/3.2 mph = 0.5 km-ish/h)
 * @param f capacity (persons, bags, tons, pieces, items, cubic metres, ...)
 * @param g weight (1/4 ton)
 * @param h power (10 hp)
 * @param i roadtype
 * Tractive effort coefficient by default is the same as TTDPatch, 0.30*256=76
 * Air drag value depends on the top speed of the vehicle.
 */
#define ROV(a, b, c, d, e, f, g, h, i) { a, b, c, PR_RUNNING_ROADVEH, d, e, f, g, h, 76, 0, VE_DEFAULT, 0, i }
#define R ROADTYPE_ROAD
#define T ROADTYPE_TRAM
static const RoadVehicleInfo _orig_road_vehicle_info[] = {
	/*    image_index       sfx                                 max_speed    power
	 *    |    cost_factor  |                                   |   capacity |  roadtype
	 *    |    |    running_cost                                |   |    weight |
	 *    |    |    |       |                                   |   |    |   |  |*/
	ROV(  0, 120,  91, SND_19_BUS_START_PULL_AWAY,            112, 31,  42,  9, R), //  0 MPS Regal Bus


/******************************/
   ENGINE_TYPE.H
/******************************/

/** Information about a road vehicle. */
struct RoadVehicleInfo {
	byte image_index;
	byte cost_factor;
	byte running_cost;
	Price running_cost_class;
	SoundID sfx;
	uint16 max_speed;        ///< Maximum speed (1 unit = 1/3.2 mph = 0.5 km-ish/h)
	byte capacity;
	uint8 weight;            ///< Weight in 1/4t units
	uint8 power;             ///< Power in 10hp units
	uint8 tractive_effort;   ///< Coefficient of tractive effort
	uint8 air_drag;          ///< Coefficient of air drag
	byte visual_effect;      ///< Bitstuffed NewGRF visual effect data
	byte shorten_factor;     ///< length on main map for this type is 8 - shorten_factor
	RoadTypeByte roadtype;
};


/******************************/
   NEWGRF.CPP
/******************************/

		EngineInfo *ei = &e->info;
		RoadVehicleInfo *rvi = &e->u.road;
		rvi->roadtype = ROADTYPE_ROAD; // default <- get from proper newgrfspec