Mary Murray Drive surrounds the park and is open to traffic 24/7 with only a few exceptions. Quick argues:
Hampton and Mary Murray Drive would come alive with more walkers, runners, cyclists, strollers, inline skaters, wheelchair users, people with dogs and animal life, more so than when the city temporarily closes the park to traffic 8 a.m.-noon Saturdays year-round and 6-8 p.m. Tuesdays and Thursdays during the spring, summer and fall. (The city's recreation Web site notes the temporary closures are "for your safety.")
There's a real appeal to the idea. It seems a fair argument that if the road can be shut down at seemingly random times without too adverse of an effect, maybe we'd be better off with it as more of a park than a thoroughfare.
You can read Quick's article for some theories on how one could deal with the parking and traffic issues.