Many workers have been affected by local tube or rail disruptions. Technically it is their job to get up earlier and find an alternative route into work. In reality, many employers arrange home working (where appropriate) which reduces stress and improves productivity.
If you don’t have an established car sharing or lift sharing scheme, you should be careful you don’t end up setting up liability for uninsured drivers. You should not be ordering or directing employees to get into a car with ‘Fred’ if you don’t know that Fred is insured. If that is a fully insured company car that is different.
Hourly paid workers are not usually paid except for the hours they work, though salaried workers may be on a different basis. You should check your contracts to see if you do in fact pay people on an hourly basis or some other way.