I once took off for a ride late in the afternoon on a 38 mile R/T rural route that I knew about but hadn't ridden yet. So I knew I wasn't going to get lost but when I was coming back, wasn't sure if I was going to make it home before it got too dark. Well, several miles to go before home, it got too dark - didn't have headlight/blinkie, couldn't see the painted white road "shoulder" (no shoulder though, pavement ended on outside right edge of painted line) strip very well anymore, the occasional car with headlights on seeming to pass way way too close & was sure wearing a yellow vest at night was a moot point. Anyway, ended up stopping (at mile 30) at a tiny regional park & called a cab for the rest of the ride home back into town - just was too dangerous to be riding a bicycle on a rural/deserted road in the dark...