As cities grow, the distance between people's homes and workplaces also grows.
This creates communities with a greater reliance on cars, higher transport costs and more vulnerability to oil price rises.
Such is Perth.
And like other capital cities in Australia, the level of car dependency in Perth has increased at a faster rate than population growth, creating traffic congestion.
Congestion is the bane of metropolitan motorists. It lengthens the working day and keeps workers away from their family and friends or from community, cultural and recreational activities.
There are also significant economic effects. The Bureau of Infrastructure, Transport and Regional Economics estimates that the cost of congestion in Australian capital cities was $9.4 billion in 2005 and will rise to $20.4 billion in 2020. In Perth, the cost is expected to increase from $0.9 billion in 2005 to $2.1 billion in 2020.
And there are productivity impacts. The State of Australian Cities 2010 report, released early last year, said the movement of goods in Australian capital cities would increase 70 per cent between 2003 and 2020.
RAC head of member advocacy Matt Brown says Perth's road network is stretched and in need of urgent attention. "There is clear evidence that our road system is under considerable stress and it is struggling to cope with the traffic we already have, and with the population growing rapidly, these problems are going to get worse," he said.
"Perth's freeways and highways are becoming carparks at rush hour and this is only going to get worse. Creating a better and more accessible public transport system is just one way to help solve the issue of congestion.
In a speech late last year, WA Chamber of Commerce and Industry chief executive James Pearson listed infrastructure bottlenecks as one of the major challenges hampering WA businesses.
Transport Minister Troy Buswell agrees. He has nominated congestion and coping with Perth's population growth as one of the priorities of his portfolio.
While Mr Buswell acknowledges that the expansion of Perth's road network is important, he believes there may be other ways of dealing with transport challenges posed by the city's growing population.
"The Government has already committed significant funds to major road projects around the city, and we're also looking to expand Kwinana Freeway between Roe and Leach highways and to work on design options to increase the capacity of the Mitchell Freeway," he said.
"But I also think we should be looking at an innovative approach to public transport and embrace the private sector in 21st century solutions. Private companies already play a significant role in our transport system and there's no reason why this relationship cannot be expanded."
There would certainly be opportunities for private sector involvement in the establishment of a light rail and bus rapid transport system for Perth.
Last month, Premier Colin Barnett told a Chamber of Commerce and Industry lunch that the introduction of light rail was under consideration, with an announcement likely early this year.
There are also growing indicators that light rail and bus rapid transit systems will be a fundamental part of a 20-year public transport master plan currently being finalised by the State Government.
Double-digit growth over the past five years, fuelled mainly by the resources boom, has also seen tremendous pressure on Perth Airport to upgrade the facilities at the primary gateway into WA.
Over the past two years, a host of projects have been undertaken by both Westralia Airports Corporation, leaseholder of the airport, and Qantas, which is responsible for its domestic terminal, with a combined $300 million-plus invested.
In November, a $500 million development was announced to reshape the airport ahead of the final full integration of the domestic and international terminals at the end of the decade.
Work will start this year on a terminal for regional airlines and a major extension of the international terminal on the eastern side of the airport to handle A380s and interstate flights for Virgin Blue.
Even though the investment is to be lauded, the problems for the airport will continue because of the need to upgrade the highway infrastructure to facilitate the full integration of the domestic and international terminals.
The price tag for the road upgrade has been estimated at $750 million and will involve the widening of Tonkin Highway plus full flyover interchanges at Leach Highway and Horrie Miller Drive intersections.
Dubbed the Gateway WA project, it has been identified as a national infrastructure priority and will underpin the long-term expansion and consolidation of Perth Airport.