When should you never start to cross at a railroad crossing?

You should never start to cross at a railroad crossing if there is not enough room for your vehicle on the far side. This is crucial because if you begin crossing without sufficient space, your vehicle could become stuck on the tracks, potentially leading to a dangerous situation where you might be at risk of being hit by a train. It is essential to ensure that there is enough clearance for your vehicle to safely exit the other side of the crossing before you enter onto the tracks.

In contrast, starting at a railroad crossing when the lights are off may not necessarily indicate danger, as it does not always mean there is an immediate threat. Similarly, the presence of another vehicle is not a decisive factor for crossing; rather, you should focus on your own vehicle and the conditions around the crossing. Lastly, while it's generally a good practice to look for trains, their absence does not automatically mean it's safe to cross if there's insufficient space. Thus, ensuring enough room on the other side is the most critical consideration when approaching a railroad crossing.