Along many main highways (including Hua Hin to Bangkok) there are distance markers showing not only the number of kilometers from Bangkok, but the distance each 100 meters. The distance markers are placed in the centre median strip with one visible to vehicles travelling in each direction. That’s 10 x 2 markers for each kilometer. Next time you want to let someone know about a location en-route, just say it by distance. For example the Tha Yang Immigration office for Phetchaburi Province residents is at the 169 KM / 500 metre mark.