The flyover bridge that you see on the left is Eastern Boulevard. Keeping left takes you to the northern suburbs of Cape Town via the N1 highway whereas keeping to the right leads to the southern suburbs.
The sign may not look that large in this photo, but did you notice the huge advert for the iPhone 4 against the side of the building on the left? That poster looks absolutely huge when viewed from your car on Eastern Boulevard. Because it's located next to a part of the road where lanes merge and traffic is accelerating out of the city, I find it dangerously distracting - especially if the advert is particularly eye-catching.
I've actually erected a mental block, forcing myself not look at the sign when traveling along that stretch of road!