If you just simply took combined provincial and Federal excise taxes plus licenses and compared it with spending on roads, it's close to 100%.
Total revenue is about $2.46B in 2019.
Government of Alberta maintenance and capital spending on bridges and roads appears to average about $1.3B/year.
The City of Calgary's net operating budget for streets is about $140M-$150M/year.
Calgary's capital sending for streets for the next several years averages to about $175.2M/year.
If we scale Calgary's spending per capita to the rest of the province, we end up with total spending of around $2.4-2.5B.
People tend to over-estimate the costs of roads, which given how much people and goods they carry are remarkably cheap (for the taxpayer).
If you're looking for a subsidized mode of transport, then that would be transit, especially in recent years as most of North America have lost the ability to build rail affordably.