I always try to leave earlier than my roommates to beat the morning rush.

For two-syllable adverbs ending in "-y", we change the "-y" to "-i" and add "-er" for the comparative form.

The bus drivers drive more dangerously when it rains than when it's sunny.

"Dangerously" is a long adverb ending in "-ly", so we use "more" to form the comparative when comparing rainy days to sunny days.

Out of all the commuters, the cyclists navigate the traffic the most efficiently.

We use the superlative "most efficiently" because we are comparing the cyclists to all the other commuters, and it is a long "-ly" adverb.