Now, just imagine the basic costs for the company/month.
1. Maintenance (including any accidents)
2. Driver salary
3. Accommodation and food
4. Annual ticket (if there any)

Also remember one thing all vehicles are running 24x7.

3. Now the public bus system.

You can go to sanaiyya from Doha easily. But if you need to go Mesaeed from Sanaiyya...!! No choice. It means you need to waste a lot of time and energy if you are depending bus system. And there is no other choice than taxi.

So, maintain your car well by doing proper service. May be you pay some 100s or 1000s for service. But it will save your precious time and valuable money for ever.