When it comes to bus and truck tires they both have in common that they use a lot of tires and the rear tires tend to be dual wheels, with double tires. This makes the checking of the tires more challenging to say the least. You have both the challenge to check the condition of the tire and it is slightly more difficult to check the tire pressure. As the tires are mainly haul tires, meant for long distances it is important to check the tire pressure regularly. Modern Tire Pressure Monitoring Systems are not working well for heavy trucks, so you need to check the pressure manually.
Running the tires with low pressure will cause increased wear and increased fuel consumption. If you drive with much too low pressure you will damage the carcass of the tire and the tire can rupture. With dual tires the wear is increased if only one is low pressure and the other is normal pressure, which can cause premature failure of the tire. If the tire has had too low pressure for a long time, the tire should be changed immediately, if it is below half of the intended pressure and the tire should be discarded. Most of the cases when a truck or a bus needs to be attended to will be because of tire problems and they are almost all attributed to low tire pressure causing blowouts.
So checking the tire pressure is something that there should be a lot of emphasis on, especially before each new long haul commences. Preventive maintenance is always cheaper than repairing and fixing things as you go when you run into problems. Both bus tire and heavy truck tires needs to be attended to regularly to both check the visual condition of the tires, the tread depth and the tire pressure in order to drive safely. Some drivers are not keen to check the pressure as it involves a bit of hassle doing it, but there is more hassle if the vehicle breaks down.
Replacing worn tires as soon as they start getting close to the limit is advisable and not trying to get the most out of the tires, as breakdowns are so expensive. It is in most cases a cost saving to replace early versus risking a blow out while en route, where there will be delays if you need to replace the tire.