1-) www.bum.com : last news from 2011 seems to failed.
2-)https://play.google.com/store/apps/details?id=com.marzki.reparkapp seems to be inactive.
3-) http://platewave.com/ focus on dating and UK only and only web and mobile app.
Chatting with people? This is what a normal messaging app does.
Chatting with nearby cars? You'd need geolocation accuracy to be continuous and very precise. Waze, a navigation app, allows crowdsourced submissions about traffic info, police, etc; it's goal-oriented and works.
Nintendo 3DS consoles will interact when they're in proximity. That's goal-oriented and works.
Several normal chat networks, like Snapchat, allow you to locate nearby users when they're in geolocation mode.
General purpose, semi-anonymous neighbor chat is just not that big of a market (yet), even when you discount a focus on cars. Yik-yak was similar by offering geofenced anonymous chat based around fixed (in real-world) locations, but they just pivoted away from anonymity.