Complex sentence: At its maximum, the slope of Baldwin Street is about 1:2.86 (19 ° or 35%)--that is, for every 2.86 metres travelled horizontally, the elevation rises by 1 metre.
Split into simpler sentences: At its maximum, the slope of Baldwin Street is about 1:2.86 (19 ° or 35%). That is, for every 2.86 metres travelled horizontally, the elevation changes by 1 metre.