There is a video of an LPG road tanker explosion occurred in Turkey. The video was captured in a cell phone camera. It shows the impact of pressure wave generated by the explosion in the form of fall of persons, light emitted during explosion, widespread damage to property and a crater in the road.
This reminds me of an incident where an LPG tanker toppled and fell on the road. Without understanding the hazard of explosion any time, passersby gathered around. Even the company officials took more than a day to put it on the road and tow away.
In another incident an ammonia tanker fell on the road. However, in this case, the road was blocked, the company officials promptly transferred the content to another vessel and cleared the area in a few hours.
Though everyone should be careful, it is the responsibility of the transporter and the manufacturer of the chemicals to ensure that transport containers are fit for road journey, the drivers know what to do in an emergency and are trained to handle the situation. Normally, the behavior of the public at large is to gather and watch. So, the driver of the vehicle, in an emergency, should caution and drive away the public to safe distance so that they are safe in case of any eventuality.