The nearest crosswalk is a lot more than 50 ft away. It doesn't make any sense to expect people to walk two blocks out of their way to cross the street in the middle of the city. The pedestrian paths along Mission Creek are only going to get busier as more buildings get built in Mission Bay and around CCA.

@oba - 50ft is not 2 blocks. Exaggeration is unbecoming.
And it is not so far out of the way that a person who is jogging or biking, already doing a physical activity, should feel is too far away. As the neighborhood develops a cross walk my be put in place on the south side of the bridge to connect park spaces on the east and west sides of the street but this is years off in the future.

4th Street is 60ft wide at this point. The walking distance, when using the nearest crosswalk (at Berry Street), is ~550ft. A typical, healthy San Franciscan walking or jogging along the water is going to take their chances and try to cross the street, without taking an unnecessary detour.

With what measuring device are you making these calculations? If you spoke to a traffic planning professional they would tell you that putting a light ~100 ft from the Berry Street light and ~200 ft from the Channel Street light, midblock, just so pedestrians wouldn't have to go out of their way would be counter-intuitive and create a more difficult traffic situation in the neighborhood.