1. As there was no bus service, I had to walk home.

Question

2. There being no bus service, I had to walk home.
(Are both the same and grammatical?)

3. As there was no seat on/in the bus, I had to stand all the way.
4. There being no seat on/in the bus, I had to stand all the way.
(Are both the same? Do we have to use 'on' or 'in'?)

5. As it was rainy, I couldn't go on a picnic.
6. It being rainy, I couldn't go on a picnic.
(Are both the same and grammatical?)

7. As there were too many cars on the street, I couldn't go fast.
8. There being too many cars on the street, I couldn't go fast.
(Are both the same and grammatical?)

Answer 1

In all these sentences, the first of each pair is fine, and the second is clumsy. The second one in each is not incorrect, just clumsy and not used much.

In the first sentence in each pair "Because" is a good substitute for "As."