Paul Krapivsky of Boston University and Sidney Redner of the Santa Fe Institute decided to build their analysis around an idealized parking lot with a single row (a semi-infinite line), and they focused on three basic parking strategies. A driver who employs a “meek” strategy will take the first available spot, preferring to park as quickly as possible even if there might be open spots closer to the entrance. A driver employing an “optimistic” strategy will go right to the entrance and then backtrack to find the closest possible spot.
Finally, drivers implementing a “prudent” strategy will split the difference. They might not grab the first available spot, figuring there will be at least one more open spot a bit closer to the entrance. If there isn’t, they will backtrack to the space a meek driver would have claimed immediately.
Krapivsky and Redner used different techniques to weigh the benefits of each strategy. For instance, they found the key for assessing the meek strategy in an existing model describing how certain molecules glom onto the ends of microtubules, thereby providing structure to living cells. Specifically, adding a GTP (guanosine triphosphate) monomer to a microtubule corresponds to a car parking after the rightmost car in the idealized lot. A car’s departure corresponds to the conversation of a GTP molecule to a GDP (guanosine diphosphate) molecule.
“A catastrophe arises when the active end of a microtubule consists of only GDP monomers,” the authors wrote. “These detach quickly, leading to a rapid decrease in the microtubule length. This latter event corresponds to a sudden drop in the span of parked cars when the rightmost car leaves and the next parked car is much closer to the target.”…[ ]