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.
The most effective way to master parallel parking is to practice. Many behind-the-wheel driving tests use cones. To begin, set up the cones in a deserted lot or very quiet street with little traffic. A spot that is 5 feet longer than your vehicle is ideal for practice. Once correctly parked, your car is 5 to 8 inches from the curb, although in some states, 12 to 18 inches are allowed. You may live in a place where you never need to parallel park, so don't skip other important aspects of driver such as merging onto a highway.