diff --git a/src/newgrf_roadstop.cpp b/src/newgrf_roadstop.cpp
--- a/src/newgrf_roadstop.cpp
+++ b/src/newgrf_roadstop.cpp
@@ -173,7 +173,7 @@ uint32_t RoadStopScopeResolver::GetVaria
 
 		case 0xF0: return this->st == nullptr ? 0 : this->st->facilities; // facilities
 
-		case 0xFA: return ClampTo<uint16_t>((this->st == nullptr ? TimerGameCalendar::date : this->st->build_date) - DAYS_TILL_ORIGINAL_BASE_YEAR); // build date
+		case 0xFA: return ClampTo<uint16_t>((this->st == nullptr ? TimerGameCalendar::date : this->st->build_date) - CalendarTime::DAYS_TILL_ORIGINAL_BASE_YEAR); // build date
 	}
 
 	if (this->st != nullptr) return this->st->GetNewGRFVariable(this->ro, variable, parameter, available);