The nearest town to Chaa Creek is San Ignacio. There are two bridges over the Macal River into San Ignacio and both are one way, so cars on one side are supposed to wait until the bridge is clear to cross. There is no formal system (like a traffic light) for regulating which side is supposed to cross at any given time.
My new friend Richard and I were standing near the bridge when a white panel van drove onto the bridge coming into town and a red pickup pulling a flat bed drove onto the bridge leaving town. They both accelerated pulling onto the bridge, clearly trying to intimidate the other driver. When they met in the middle of the bridge, they pulled to within inches of each other and then stopped. At this point in New York, both drivers would have gotten out of their vehicles and started screaming at each other, but in San Ignacio they just seemed to meet and wait.