‘As well as’ can only be followed by a noun or +ing form.

It cannot always replace ‘and’ because it cannot be followed by ‘SVO’ sentences (Subject-Verb-Object)

Common mistakes:

‘The number of houses has increased as well as more roads have been built‘.

Correction:

‘The number of houses has increased and more roads have been built’.

Other options:

‘The number of houses has increased as well as (the number of) roads’.

NB The same is true for ‘In addition to’ and ‘together with’.

e.g. ‘In addition to/As well as/Together with the increase in the number of houses, more roads have also been built.

‘More houses have been built, together with/as well as/in addition to more roads’.