Tolls raise costs, reducing demand without full substitution Steps:

• Tolls increase the effective price of using major roads.
• Higher prices reduce quantity demanded per the law of demand, decreasing journeys on major roads.
• Some drivers may forgo trips entirely due to added costs, rather than switching routes.
• Minor roads lack capacity or convenience to absorb all diverted traffic, so usage does not rise.

Why A is correct:

• Law of demand predicts reduced major road journeys from tolls; incomplete substitution keeps minor road journeys stable, as not all trips shift or minor roads can't handle more volume.

Why the others are wrong:

• B: Tolls do change major road usage by raising costs and curbing demand.
• C: Assumes full traffic shift to minor roads, ignoring foregone trips and capacity limits.
• D: Ignores tolls' price effect, which reduces major road journeys.

Final answer: A