A congestion charge for central Auckland
Auckland Council is consulting on a $5 congestion charge for private vehicles entering the city centre between 7 am and 9 am on weekdays. About 60,000 vehicles make that trip each day. Council modelling predicts the charge would cut peak car trips by 12% and raise about $66 million a year over 250 weekdays. Doubling the charge to $10 would cut trips by only 20%, the same modelling says. The revenue would fund $40 million of bus lanes and more frequent services, lifting bus capacity by 15%; currently 30,000 people bus into the centre each day. Retailers argue that foot traffic would fall 8% and that low-paid workers who drive - many earning $23 an hour and commuting from suburbs with no frequent bus - would be hardest hit. The council's own equity report notes that 18% of peak drivers have no realistic alternative. The council must decide whether to introduce the charge, and at what level.
1. Using supply and demand, explain how the $5 charge is expected to reduce peak car trips, and calculate the price elasticity of demand between $5 and $10. Is demand elastic or inelastic?
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A congestion charge is a tax on driving into the city at peak. It raises the private cost of a trip, shifting the supply curve for car trips upward (or reducing quantity demanded along the demand curve). At $5, the quantity of peak car trips falls from 60,000 to 52,800, which is 12% fewer.
Elasticity between $5 and $10: Quantity at $5 = 52,800; at $10 = 48,000 (20% below 60,000). %ΔQ (midpoint) = (52,800 − 48,000) / 50,400 × 100 = 9.52%. %ΔP (midpoint) = (10 − 5) / 7.5 × 100 = 66.7%. Price elasticity of demand = 9.52 / 66.7 = 0.14.
Demand is highly inelastic in this range. That is expected at peak: commuters have fixed work hours, few substitutes and sunk housing choices. Inelastic demand means a higher charge cuts trips only a little but raises much more revenue. At $10, revenue = 48,000 × $10 × 250 = $120 million, compared with 52,800 × $5 × 250 = $66 million at $5.
Judgement: the charge reduces congestion, but the response is modest; the biggest effect may come from the bus investment, not the price alone.
2. Explain who bears the burden of the charge and discuss the equity issue for the 18% of drivers with no realistic alternative.
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The burden falls mainly on drivers because demand is inelastic. Drivers with no realistic alternative (18%) will pay the charge and keep driving; they bear the full $5 or $10 per trip. Drivers with alternatives may switch to buses, change travel times or carpool, avoiding the charge.
Equity: $5 each way is $10 a day, or $2,500 a year for a 250-day commuter. For a worker on $23 an hour full-time (about $47,840 gross), that is about 5.2% of gross income. For a worker on $120,000, it is about 2.1%. The charge is regressive in isolation.
But the revenue is ring-fenced for buses. If low-income drivers switch to improved buses, they may gain; if they cannot, they are worse off. The 18% with no realistic alternative are the key equity concern. Exemptions, a low-income rebate or a discounted weekly cap would reduce the regressive effect, but exemptions also weaken the congestion signal.
Judgement: the charge is efficient but not automatically fair. Fairness depends on how the revenue is used and whether alternatives are in place before the charge starts.
3. Evaluate whether the council should introduce the charge at $5, at a higher level, or not at all.
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At $5: 7,200 fewer car trips per day, $66 million revenue and $40 million of bus investment. The bus capacity rise (15% on 30,000 passengers = 4,500 extra spaces) may absorb some switchers; 7,200 drivers cannot all fit, so some will change time or destination.
At $10: 12,000 fewer trips and $120 million revenue. The extra $5 cuts only 4,800 more trips than the $5 charge, so the marginal congestion benefit is falling while the burden rises. If the goal is revenue for public transport, $10 is more effective; if the goal is to reduce congestion fairly, $5 is better.
Retailers' 8% foot-traffic claim: the net effect on retail is unclear. Some drivers will stop coming; bus passengers may increase. The council should monitor.
Decision: introduce the charge at $5, ring-fence revenue for buses, and include a low-income rebate or weekly cap. This captures most of the congestion benefit with a smaller equity cost. A $10 charge should be considered only after bus alternatives are in place and if congestion remains severe. Not introducing the charge leaves the congestion externality unpriced.
Judgement: the council's choice depends on how it weights efficiency, equity and revenue. On the evidence, a $5 charge with a rebate is the most defensible balance.