Explanation:

- Speed limits being adjusted can be referred to by several terms, but typically means lowering the speed allowed for vehicles.

- Option 1: Shortened - Decreasing length, not related to speed adjustments.

- Option 2: Scaled - Often used to refer to adjusting proportionally or resizing, not directly relevant to speed limits here.

- Option 3: Lessened - Suggests reduction but is not the common term for describing speed limits.

- Option 4: Reduced - This is the standard term for decreasing speed limits on roads. It's precise and contextually accurate.