I found a post I like on a blog that has probably been abandoned, no post since September last year.
1. Greed – They realised that by crossing the road there was something in it for them. Either something waiting for them or something to be gained. Either way, greed is a powerful motivator and most characters would cross a road for it (some would cross deserts, mountains, or outer space for it).
2. Love – Isn’t that sweet? Their true love is on the other side or they will prove their love by crossing. Doesn’t matter, either way, love is a powerful motivator.
3. Loss – Someone who has lost their way or lost a love one may cross the road just wondering whether the other side offers them anything to take away the pain. Or they may have made a promise to someone who is now gone and crossing the road will help them keep it.
4. Curiosity – Not such a good motivator because usually it is used when there is no good reason for characters to act in a certain way and so they ‘just want to see’ something. Still, if you’ve established your character as someone who likes to stick their nose into other people’s business you can probably make curiosity work.
5. The next logical step – If your character is on route somewhere then crossing the road might simply be the next logical step on their journey.