Micro-trenching installs fiber in a saw-cut slot about an inch wide and 8 to 16 inches deep, usually along the edge of a street. It is the fastest, least disruptive way to put fiber through finished pavement — and the most argued-about method in the industry, because shallow has consequences.
How it works
A cutting wheel slices a narrow, clean slot in the asphalt; crews vacuum out the spoil, lay one or more small ducts at the bottom, then backfill with a flowable grout and cap it flush with the surface. Production can hit thousands of feet per day with a lane closure instead of an excavation, which is why dense cities and campus environments love it. The fiber is then blown or pulled through the duct like any other conduit build.
The argument for — and against
For: speed, cost, minimal restoration, and almost no disruption to traffic, trees, or buried congestion below — the slot rides above the existing utility layer. Against: that same shallowness. Future road milling and repaving can find the duct; freeze-thaw works on shallow cuts; and a slot at the gutter line lives in the road's wettest, most stressed zone. Some cities that embraced early micro-trenching later paid in street-maintenance conflicts, so many now regulate exactly how deep, where in the roadway, and with what backfill it's allowed.
The engineering answer isn't "good" or "bad" — it's where. Under a road due for reconstruction next year: a poor bet. Along a stable street where boring would cost 5× more: often the right call.
How it compares to the alternatives
Versus directional boring: micro-trenching is faster and cheaper in pavement but shallow and surface-bound, while boring travels deep beneath everything at higher cost. Versus plowing: no contest in open ground (plowing wins) and no contest in a downtown street (plowing can't). Real city builds mix all three, block by block — matching the method to the ground is most of the craft.