Gradable Adverbs

[Simonmm]

To all,

I hope someone can help with this question smile

A student wrote the following two sentences.

Driving is extremely faster than walking.
Walking is highly more convenient than taking the bus.

There are, I believe, a few different adverbs you can use here, but it's a question of which ones.
Does anyone know the rules of which gradable adverbs you can use with which comparative adjectives?

Thanks in advance for any assistance.

[Alan]

There is no 'rule' predicting which words will be acceptable, merely conventions of usage. 'Far' and 'much' are the most common/useful.