It's methane. While methane is a more potent greenhouse gas than CO2, there is over 200 times more CO2 in the atmosphere. Eg-CO2 levels are 380 ppm (parts per million) while methane levels are 1.75ppm.Hence the amount of warming methane contributes is calculated at 28% of the warming CO2 contributes. Here is a graph of the various forcings that influence climate (methane is CH4, right above CO2).g-CO2 levels are 380 ppm (parts per million) while methane levels are 1.75ppm. Hence the amount of warming methane contributes is calculated at 28% of the warming CO2 contributes. Here is a graph of the various forcings that influence climate (methane is CH4, right above CO2).
A 25 feet distance is required between the two cones to test  parallel parking skills. The cones are assumed to be parked  vehicles in the test.
Municipal and Federal parking regulations vary by locaiton and agency. From a review of Federal, state and local codes, the range of parking space widths varies from about 8.9 long wide to about 10.9 feet with apparent convergence around 9 feet long. Length appears to vary more, presumably explained by parallel parking requiring more length than head-in or angled parking. Lenght varies from nearly 25 feet long for parallel parking and to as little as 19 feet long, with 20 feet appearing to be a common length.