Pavement

Short-term traffic variations may occur as a result of a range of factors including:

• seasonal variation on roads in tourist areas
• school holidays
• grain harvests
• events (e.g. local show days, race days)
• staging of construction or rehabilitation work.

Designers need to be aware of the impact of undertaking sprayed seal work at a time when the traffic conditions vary from that applicable to normal use. Where possible, the impact of short‑term variation should be minimised by avoiding undertaking work during, or shortly before, abnormal events. Generally, the traffic volume used in seal design should be that estimated to apply at the time, or within the first few months, of sealing. The influence of anticipated weather conditions coinciding with the expected higher traffic volumes should also be considered in determining design application rates.

It is suggested that a design is carried out for both traffic conditions (normal and short term), and final design rates of application determined taking into account risk factors such as potential loss of aggregate (low binder rates) and potential flushing (high binder rates).