--- a/roadveh_gui.c	Wed May 11 15:31:10 2005 +0000
+++ b/roadveh_gui.c	Wed May 11 16:17:03 2005 +0000
@@ -33,7 +33,7 @@
 	SetDParam(5, ymd.year + 1920);
 }
 
-static void DrawRoadVehImage(Vehicle *v, int x, int y, VehicleID selection)
+static void DrawRoadVehImage(const Vehicle *v, int x, int y, VehicleID selection)
 {
 	int image = GetRoadVehImage(v, 6);
 	uint32 ormod = SPRITE_PALETTE(PLAYER_SPRITE_COLOR(v->owner));
@@ -47,12 +47,11 @@
 
 static void RoadVehDetailsWndProc(Window *w, WindowEvent *e)
 {
-	Vehicle *v = GetVehicle(w->window_number);
-	StringID str;
-	int mod;
+	switch (e->event) {
+	case WE_PAINT: {
+		const Vehicle *v = GetVehicle(w->window_number);
+		StringID str;
 
-	switch(e->event) {
-	case WE_PAINT:
 		w->disabled_state = v->owner == _local_player ? 0 : (1 << 2);
 		if (!_patches.servint_roadveh) // disable service-scroller when interval is set to disabled
 			w->disabled_state |= (1 << 5) | (1 << 6);
@@ -126,33 +125,33 @@
 			str = STR_8813_FROM;
 		}
 		DrawString(34, 78, str, 0);
-		break;
+	} break;
 
-	case WE_CLICK:
-		switch(e->click.widget) {
+	case WE_CLICK: {
+		int mod;
+		const Vehicle *v;
+		switch (e->click.widget) {
 		case 2: /* rename */
+			v = GetVehicle(w->window_number);
 			SetDParam(0, v->unitnumber);
 			ShowQueryString(v->string_id, STR_902C_NAME_ROAD_VEHICLE, 31, 150, w->window_class, w->window_number);
 			break;
 
 		case 5: /* increase int */
 			mod = _ctrl_pressed? 5 : 10;
-			goto change_int;
+			goto do_change_service_int;
 		case 6: /* decrease int */
 			mod = _ctrl_pressed? -5 : -10;
-change_int:
-			mod += v->service_interval;
+do_change_service_int:
+			v = GetVehicle(w->window_number);
 
-			/*	%-based service interval max 5%-90%
-					day-based service interval max 30-800 days */
-			mod = _patches.servint_ispercent ? clamp(mod, MIN_SERVINT_PERCENT, MAX_SERVINT_PERCENT) : clamp(mod, MIN_SERVINT_DAYS, MAX_SERVINT_DAYS+1);
-			if (mod == v->service_interval)
-				return;
+			mod = GetServiceIntervalClamped(mod + v->service_interval);
+			if (mod == v->service_interval) return;
 
 			DoCommandP(v->tile, v->index, mod, NULL, CMD_CHANGE_ROADVEH_SERVICE_INT | CMD_MSG(STR_018A_CAN_T_CHANGE_SERVICING));
 			break;
 		}
-		break;
+	} break;
 
 	case WE_4:
 		if (FindWindowById(WC_VEHICLE_VIEW, w->window_number) == NULL)