A driver is transporting a heavy load of materials. What calculation is required to ensure the vehicle does not exceed its legal weight limit under LTO and OHS standards?

1. Ensure that the combined weight of the empty vehicle, passengers, and cargo does not exceed the Gross Vehicle Weight Rating (GVWR)
2. Add the tire pressure values of all four tires and ensure the sum is below 150 PSI
3. Divide the vehicle's engine horsepower by the total passenger weight
4. Ensure the vehicle length is less than the cargo width multiplied by two