These drivers probably don't know that even at only 30mph a dog will fly forward and hit the first solid object it meets with a force equivalent to 25 times its own weight - which is likely to kill it. And if a dog jumps onto the driver's lap, or into the driver's footwell, this could very easily cause a complete loss of control.
Overall vehicle safety has made massive progress in recent years, in every area. Humans must wear seat belts and airbags are standard, and all modern commercial vans now include safety bulkheads. So what about transporting dogs? The UK's Highway Code (section 57) is actually very strict about the safety requirements:
Unless the dog is carried in the cargo area, ideally in a cage, the options for safe travel on the passenger seat are limited - a crash-tested safety harness for any size of dog, held in place with the vehicle seat belt or, if it's a small dog, a crash-tested cage that fits on the front seat.
SHERPA Harnesses

Sherpa crash-tested safety harnesses have a step-in design that makes them easy to fit and remove. They work with the existing seatbelts so the dog can sit, stand, or lie down. They double as a walking harness - attach a lead - and are comfortable enough for all day use. Be sure to turn off the passenger airbag if the dog is travelling on the passenger seat.
4pets Caree crash-tested dog cages

For smaller dogs, the 4pets Caree crash-tested pet carrier is also held in place with a seat belt or - a quicker and easier system if available - into the van's ISOFIX hooks, the system designed for child car seats.