D: This refers to the change of the physical environments to make space for transport systems.  

Exp: When deforestation happens, it affects all flora and fauna species that rely on the physical environment, leading to the loss of natural habitat. 

E:  For example, the construction of the Bukit  Timah Expressway divided Bukit Timah Nature Reserve from the Central Catchment  Nature Reserve, which threatened the survival of some endangered forest species in Singapore.

D: This refers to the measure of greenhouse gases emitted to support human activities. Greenhouse gases trap heat and keep the  Earth warm. 

Exp: When there is an excessive concentration of greenhouse gases, it leads to the enhanced greenhouse effect - warmer temperatures. 

Eg.: For example, an individual’s carbon footprint when travelling by plane is 62kg from  Singapore to Kuala Lumpur.

D: This refers to the better ability of the elderly and disabled to move from place to place, and access basic goods and services. 

Exp: When transport systems allow for the elderly and disabled to move more freely to access different services, it results in enjoying a better standard of living.

Eg.: For example, the provision of Silver Zones allows for these people to cross the roads with ease of mind, as the road speed limit is reduced to 40 km/h and curbs are lowered.

D: This occurs when road usage approaches or exceeds road capacity. 

E: When there is high traffic volume, coupled with slow speed, it results in longer travelling time for all road users, causing drivers to lose concentration, and posing a safety risk.  

Eg.: For example, in Singapore, an extra travelling time of 5 days and 15 hours was spent in 2019 due to traffic congestion. 

D: This refers to laws and policies to ensure road safety and also to educate all road users on practising good safety habits 

E.g.: A campaign, "Road Safety for All, " focuses on practising good road safety habits.

E: When establishing clear guidelines and consequences for violation is in place, 

Advantage (+): help to raise awareness and change road user behavior through educational initiatives. 

Disadvantage (-): there is a potential for over-reliance on enforcement which overshadows the importance of individual responsibility and graciousness on the road.

OR

D: This refers to embarking on car-lite policies to drastically reduce car usage by encouraging the use of alternatives such as public transport modes.

E.g: Singapore's introduction of a Certificate of Entitlement (COE) since 1990 as an additional cost to the car discourages people from purchasing one due to high cost. 

E: When car-lite policies are in place, 

Advantage (+): it helps to limiting vehicle growth and thus reduces the need to increase Singapore's road capacity.  

Disadvantage (-): it makes owning a car in Singapore extremely expensive for citizens to afford. 

D: This refers to the process of forecasting the operation, provision and management of infrastructure and services for various transport modes to meet current and future usage needs in shaping the demand for travel and distance needed for travel on land. 

E: For example, Singapore's Land Transport Master Plan (LTMP) 2040 is a long term plan to shape the future of land transport where it aims to develop a network which is convenient, well-connected and fast for all commuters. 

E: When integrated planning is done, 

Advantage (+): it results in well-planned towns and cities with reduced travel time, and lessens the need to travel far or make frequent single trips. 

Disadvantage: it requires close coordination and communication between different stakeholders which takes a lot of time and huge investments to ensure effectiveness. 

D: This refers to installing barrier-free transport facilities with special features for the aged and disabled so as to develop an inclusive transport systems.

E: For example, the Green+ Man scheme was implemented in Singapore to give elderly pedestrian and PWDs up to 13 seconds more green man time when crossing the roads.

E: When there is a provision of range to provide mobility options for different groups of people, 

Advantage (+): it helps people of various needs get to where they want to go, safely and efficiently which offers convenience at every turn. 

Disadvantage: it requires installing barrier-free transport facilities that is expensive and requires time for the government to deploy these features at places of high needs to prevent wastage of resources. 

D: This refers to investing in information and technology to explore ways to make transport systems more sustainable to improve mobility as well as safer and more environmentally friendly transport modes. 

E.g.: For example, in Singapore, the use of SGBus apps indicate the bus arrival timing for passengers to plan their schedule accordingly. / In Singapore, the increased use of Electric vehicles (EV) for private and public vehicles help reduce carbon emissions. 

E: When research and development (R&D) is done, 

Advantage (+): transport assets are more efficiently distributed and deployed which effectively meets transport demands and reduces waiting time and cost.

Disadvantage: it requires a lot of time and investments which may lead to increased cost of public transportation.