Implementing bus and other public transportation systems comes with a variety of both positive and negative externalities. One potential positive externality is associated with the increase in pedestrian-only spaces. Suppose that there is a $2 per-unit positive externality associated with these spaces. It the government wished to resolve this externality entirely, what would be its total tax revenue or subsidy expenditure? Enter a positive value if the government would earn tax revenue' Enter a negative value if the government would implement a subsidy. 2?. $10 $1 3% 31 sin 3: vi :3 :1 M b \\ZSHS'Dqsqmll