Brook Trout are not genetically programmed to die after spawning as are the Pacific species of salmon. Spawning is however difficult and dangerous and many fish do die during spawning. The length of the incubation period varies according to the temperature - at lower temperatures the incubation period is longer.
More than half of the total length of the German autobahn network has no speed limit, about one third has a permanent limit, and the remaining parts have a temporary or conditional limit. Some cars with very powerful engines can reach speeds of well over 300 km/h (190 mph).
For instance, a speed limit decrease from 60 mph (100 km/h) to 30 mph (50 km/h) might use a transition speed limit of 45 mph (70 km/h) or 50 mph (80 km/h). The minimum transition speed zone length usually allows for the placement of REDUCED SPEED AHEAD signs and a sufficient speed zone length to achieve compliance.