Satellite tracking may solve the problems of the Drogheda bypass and Dublin Port but more comprehensive road reform is vital, writes James Nix.
The prospect that many drivers would not pay tolls to use the Drogheda bypass was raised at public inquiry stage - and dismissed by the National Roads Authority as something that would never happen.
Defenders of the toll scheme pointed to Dublin's East and West Link bridges. However, unlike Drogheda, the tolled Liffey crossings offer enough comparative advantage over alternative routes to attract motorists and truck drivers alike.
Coupled with the problem in Drogheda there is a growing realisation that the Dublin Port Tunnel - whether completed to standard height or not - has been oversold. How, for example, will southbound or westbound trucks be directed north through the tunnel and around Dublin's M50?
Drogheda's is a case of not being able to direct vehicles along a corridor specifically built to facilitate their movement. The potential underuse of the Dublin Port Tunnel is more complex: city authorities need to be able to monitor trucks to make sure they stick to the approved route.
Modern "pay-as-you-go" road-charging offers a way to address both issues.
Trucks are monitored via satellite and charged for each kilometre travelled. The on-board unit fitted to each lorry can be calibrated to reflect the weight of the vehicle and its emission levels. Tariffs can be set to reflect the value of road space - e.g., night-time delivery can be made more cost-effective.
With a national per-kilometre charge hauliers would take the Drogheda bypass. Why? Because going through the town would cost the same and take longer.
With regard to the Dublin Port Tunnel, truckers who trundle down Dublin's quays with no delivery to make in the area would show up on satellite and could be penalised.
The technology to achieve this has already been adopted in Germany and the system will operate from September. On average trucks will be charged 12.4 cent per kilometre. In Britain, Transport Minister Alistair Darling is promoting the idea of replacing road taxes with "pay-as-you-go" charges.
German legislation allows the receipts from satellite tolling to go directly to road construction companies.
In Ireland, builders of the Drogheda bypass and any other route currently tolled could be paid out of the total pool of receipts raised from a nationwide "pay-as-you-go" system. This would have the additional benefit of avoiding adverse impacts on public spending.
The removal of heavy goods vehicles from Drogheda was based on a fragile assumption - that commercial users would pay to use relatively short bypasses. That assumption has now been exposed.
But, if outcome is what matters, it is not simply enough to change the revenue-earning mechanism of Ireland's roads programme.
The stated purpose of road building in Ireland is to deliver balanced regional development.
Building five motorways feeding into Dublin is the method sought to achieve this. In other words there is an implicit assumption that having all motorways going into the capital city will boost inter-regional trade.
This is nonsense. Even the 19th century British administration realised that upgrading links to Dublin would exacerbate the suction effect of the capital; hence the subsidised construction of the (now closed) Sligo-Galway railway line.
Dublin's growing hegemony is obvious. Tourism expert Carmel Needham points out that Dublin's share of Ireland's tourist cake has gone from 29 per cent to 36 per cent since 1995.
Passenger throughput at Shannon Airport is slipping: down 2 per cent, with tourism spending in the Shannon region down 4 per cent.
Dublin Airport, on the other hand, is struggling to cope.
Improving roads to Dublin heightens the capital's relative importance in relation to Cork, Limerick, Galway and Waterford. In turn, these cities reduce their dependence on each other. To remain with an example from the tourist sector: Galway-to-Dublin Airport buses are recording robust growth. By contrast, there is one direct Galway-to-Shannon Airport bus per day!
A key hindrance to the provision of a Galway-to-Shannon bus service is the patchy quality of the roads - in other words the aim for regional balance translates into a need for better roads from Ennis to Gort, not from Rochfortbridge to Moate.
The latter section is earmarked for motorway under the M4/M6 project but a new road between Ennis and Gort - even though it would leave Galway one hour from an international airport - is not a priority.
In the years before the Celtic Tiger, five motorways converging on the M50 might have been defended in order to boost the critical mass of Dublin.
But that argument is completely gone. Today Dublin is being hit by significant dis-economies of scale.
As Dublin's congestion bill mounts, it is now more than ever in the interests of the capital to see counterweight cities prosper.
Academic literature on developing counterweight cities must also be factored in.
According to Britain's Standing Advisory Committee on Trunk Road Assessment, linkages between counterweight cities - rather than direct to the capital city - are instrumental to balanced development.
Adapting the 1999 National Development Plan is a matter of detail that all political parties must engage in. Across the spectrum the emphasis must be on getting reform right: the fact that tolled bypasses or the layout of the network don't work has yet to be grappled with by Dáil Eireann.
In 1999, the motorway plan produced under the auspices of the European Committee of the Regions was not consulted (the plan advises building roads which can later be "expanded out" to motorways - Sligo-to-Cork is earmarked for such a route - and the Dublin-to-Cork highway runs via Waterford). In addition, road/rail complementarity wasn't addressed by the 1999 plan.
Likewise, Ireland's Kyoto pledge - which effectively caps car-oriented development - was never factored in.
The question is simple: do we keeping stressing roll-out or do we shift the emphasis to outcome?
James Nix is a transport researcher at the Dublin Institute of Technology (james.nix@dit.ie)