Metric Conversion Having Little Local Impact
NH Department of Transportation Converting to Metric Measurements; Vendors Prepared to Provide Goods and Services in Metric and American Standard Units
September 30, 1996 was the date Congress set in 1991 for federally funded projects, including highway projects, to be in metric units. Many officials thought that conversion from English units at the federal level would result in conversion at the state and then the local levels. Metrication has occurred at the New Hampshire Department of Transportation (NHDOT), but not at the local level.
Will local conversion be necessary? If so, to what extent? To answer these questions, one needs to understand the current state of conversion by the NHDOT and by private contractors and material suppliers.
The Current Situation
Last fall Congress extended the metrication completion date until September 31, 2000. However, the NHDOT and over 40 other state highway agencies are proceeding. The NHDOT has for some time conducted surveys for highway projects in metric units. Its designers prepare plans and specifications for many projects in metric units. Its Standard Specifications for Road and Bridge Construction in dual units is being prepared for printing and will be in use by May 1, 1997.
The highway industry prepared for the 1996 deadline by redesigning construction equipment and modifying manufacturing specifications. The new equipment and specifications enable private contractors and suppliers to do business in either metric or English units. The following list illustrates industry adjustments for services and materials most frequently needed by local road departments.
Modern asphalt and concrete batch plants can provide materials for metric or English units mix designs. (Non-modernized plants provide mixes in English units only.)
Modern paving machines can lay asphalt in either inches or millimeters.
Sand and gravel companies’ sorting screens have been in both units for many years. With computerized equipment, suppliers can provide graded mixes for a metric or a English units mix design.
Culvert manufacturers increased their manufacturing tolerances to accommodate both units. For example, suppliers can sell a 12 inch culvert as a 300 mm culvert.
Guardrails will remain in the current English unit dimensions. Metric purchases and installations will be in equivalent dimensions.
The Future
Local highway industry sales personnel, engineers, and crews have traditionally used English units. Contractors and suppliers who have municipalities and the private sector as major customers will likely continue to operate in English units.
Consulting engineers were educated in English units. Firms that concentrate on state and federal work might develop more expertise in metric, and thereby provide less service to municipalities. This is likely to occur with only a few engineering firms.
Manufacturers of sign hardware – faces, blanks, posts, bolts, etc. -- will produce separate materials for metric and English dimensions. Although sign messages will be in English measures, the NHDOT and other state agencies will specify metric sign hardware for federally funded projects. For signs used infrequently by municipalities but often by the NHDOT, local road departments might have to special order sign hardware. Distributors will stock English unit signs hardware for frequently purchased items.
The NHDOT conversion to metric will affect some municipal engineers and planners. Although right of way plans will be in dual units, engineers and staff who review NHDOT construction plans will increasingly find drawings and specifications in metric units. Also, as-built drawings for metric unit projects will also be in metric.
Impacts will increase only if the political and economic situation changes significantly. These situations appear more likely to remain as they are than to shift toward metric units. The highway industry’s recently revised specifications, which accommodate both metric and English units, should remain in force for some time. Local contractors, suppliers, and engineers are likely to see municipal and private customers as a desirable market, and continue to serve them in English units.