Transport and sustainability

Order from lowest to highest environmental impact per person on an urban journey and justify the order: single-occupancy car, bus, bicycle and underground.

Explain what sustainable mobility is and mention three specific actions a city can take to promote it.

A local council wants to reduce traffic in the city centre. Analyse these four measures — cycle lane, pedestrianisation, park-and-ride car park on the outskirts, and shuttle bus — and order them by speed of implementation and expected impact, justifying your criteria.

The graph compares CO₂ emissions per passenger per kilometre for various modes of transport. Calculate the emissions for travelling to school and back ($15\ \text{km}$ in total) by car and by bus, and state how many times more one option emits compared to the other.

Electric cars do not emit tailpipe gases while driving, but does that mean they are "zero emission"? Reason your answer using the life cycle approach: battery manufacturing and the source of electricity.

A mobility audit at your secondary school (600 students) reveals that 45 % arrive by private car (with an average occupancy of 1,1 students/vehicle), 30 % by bus, and 25 % on foot or by bicycle, causing severe traffic jams and hazardous situations at the gate at 8:00.

1. a) Design a school mobility plan with three specific technical or organisational measures aimed at reducing car trips by at least half within one school year.
2. b) Define two verifiable quantitative indicators (specifying their calculation formula and unit of measurement) for the school management to evaluate the plan's effectiveness on a monthly basis.
3. c) Justify a low-cost physical intervention on the public street in front of the school (tactical urbanism) that increases the safety of students who commute actively.

Rank these transport energy sources from lowest to highest emissions when driving/moving and justify the order: petrol, electricity from renewable sources, diesel and human power (bicycle).

Twenty students who travel $4\ \text{km}$ a day by car to get to school decide to switch to cycling. With these figures per passenger: $120\ \text{g}$ of CO₂ per kilometre by car versus $0\ \text{g}$ by bike, calculate how many kilograms of CO₂ are avoided in a month of 20 school days.

The construction of a 400 km high-speed railway line has generated a carbon footprint of 1,5 million tonnes of CO₂ equivalent due to earthworks, tunnels, and concrete work on viaducts. In that corridor, travelling by plane emits 120 g of CO₂ per passenger·km, while the train emits 24 g of CO₂ per passenger·km with the current electricity mix.

1. a) Calculate how many full passenger trips by train (replacing the plane) are needed to offset the initial impact of the infrastructure.
2. b) If the line carries 3 million passengers per year and 70 % of them shift from flying, predict in how many years the environmental payback of the project will be achieved.
3. c) Justify how this payback period would change if the country's electricity mix shifted from 50 % to 90 % renewable generation.

Explain what a "protected cycle lane" is and why it increases bicycle use much more than a simple line painted on the road.

A city bus consumes the equivalent of 8 litres of diesel per $100\ \text{km}$ and carries an average of 20 passengers; a car uses 6 litres per $100\ \text{km}$ with a single occupant. Calculate the consumption per passenger per $100\ \text{km}$ in both cases and comment on the result.

A 1300 kg passenger car consumes 5,5 L of petrol per 100 km when only the driver travels. Each additional 75 kg passenger increases the vehicle's consumption by approximately 0,1 L per 100 km (data: burning 1 L of petrol emits 2,3 kg of CO₂).

1. a) Quantitatively refute the statement 'carpooling pollutes the same as driving alone, it is just shared', calculating and comparing emissions in grams of CO₂ per passenger·km when only the driver travels versus when 4 people travel together.
2. b) If carpooling is promoted in an industrial estate with 1200 workers and average occupancy rises from 1,1 to 2,2 people per vehicle, predict how many fewer cars will circulate and how many square metres of parking space will be freed up (estimate 12 m² per space).
3. c) Justify why reducing the number of vehicles by 10 % during peak hours can reduce time lost in traffic jams by more than 30 %.