For a long time streets were either dirt or macadam – metal (small stones) laid and held together with clay cement. Grading or levelling was often limited, and some roads were crossed by streams or ran through swampy ground. Where possible, some improvements were carried out, such as bridges to cross streams. In winter streets were muddy and dangerous, often filled with slush composed of horse dung and grit. Auckland got a street sweeping machine as early as 1876, but most dung was still picked up with pans and brooms. In summer dust was a severe nuisance, and water carts had to be used to minimise it.
Early advances in street building
Forming, metalling, kerbing and channelling streets was the main focus in the late 19th century. The majority of streets constructed until the early 1900s were macadam, and were eminently suitable for horse-drawn vehicles.
Asphalt and wood-block paving were two other methods for forming streets. Wood-block paving was slightly cheaper as it did not require the same skill to lay and repair as asphalt. It could be installed by local authorities, whereas asphalt often had to be laid by skilled contractors. Both materials were an improvement over macadam for strength and durability. Although many cities began to use these new methods, the majority of streets in cities and towns up to the 1920s remained macadam.
Wellington got its first steam-driven road roller in 1887. It was so noisy and hard to stop that a roadman with a red flag was required to walk 27 metres in front of it to warn other traffic. But the lumbering machine startled a tramcar horse, which took fright, pulling its car about 3 metres off the rails. The vehicle was thenceforth restricted to night-time use.
With the advent and rapid growth of motor traffic by the 1920s many centres were forced to look for some more permanent form of road surfacing. The need was for dust-free streets, capable of providing a smooth ride at far higher speeds than a horse-drawn vehicle could travel. Stronger road surfaces were also required to reduce the damage done by faster, heavier vehicles.
The most common material adopted was asphalt or bitumen, used widely from the 1920s. It was strong, and quieter for traffic than wood blocks or macadam. It also eliminated the dust nuisance. Over the next decade many local authorities raised loans and carried out programmes for repaving the principal streets in cities.
Paving projects that started in the 1920s slowed in the 1930s as a result of the economic depression. The depression also had an impact on street construction when work was created for the unemployed making new streets. Street works slowed again with the outbreak of the Second World War. With limited staff, funds and resources, most local authorities had to suspend paving programmes and limit street maintenance.
The 1950s saw a period of significant investment and upgrading of streets. Many centres faced a growing need to improve streets that had seen little maintenance since the late 1930s. New town-planning legislation led to the need for major street reconstruction in cities. Modern motorised machinery such as graders, asphalt layers and road rollers replaced horse-drawn equipment and increased street-building efficiency – although the shovel remained an essential tool. Motorised street sweepers and water tankers also became common for cleaning.
Once this backlog of road construction and maintenance was met, attention turned to maintenance and the provision of high-quality surfacing. In 2009 asphalt was the material predominantly used on New Zealand streets. Research was looking to develop asphalt that was quieter to drive on, smoother and more durable, with increased skid resistance and less splash and spray in wet weather.