On Your Streets: Curbs

Have you noticed the street curbing (or curbs) lately? What is the material? Concrete, granite, marble, stone, or none at all?

I’ve pondered sidewalks before, but not really the curb material. Why bother to notice, you ask? From a transportation perspective, it’s interesting, because curbing is something specified in sidewalk and road construction plans. Curbs exist to protect pedestrians from traffic and to channel runoff.

Curbs typically exist in neighborhoods, villages, towns, cities, etc., as opposed to on stretches of highway and less dense areas of development. Their style, shape, construction methods, materials and age varies. Until living in Vermont, I never noticed granite curbing, which is popular (though not a rule) in recent sidewalk reconstruction throughout Vermont villages. Older curbs from the early 20th century are concrete. While home in New York recently, I noticed the curbs were either concrete or rough cut stone blocks with cement mortar. When living in North Carolina, I remember thinking it odd that in many neighborhoods, the lawn ran into the street without a curb, and many of the front yards were covered in (long leaf) pine straw in addition to grass. What is the reason for the difference?

A newer granite curb in a Vermont village.

I would guess climate factors into the decision, and availability of material. Vermont and New Hampshire are known for granite, and it is more durable for our harsh winters, road salts and other de-icing solutions and against plows. The climate in Southern Pines, NC was much milder compared to other places I’ve lived, and snow plows of any kind are rarely needed.

The older curbs in Vermont are often concrete, of varying composition. The smaller/less visible the aggregate (pebbles mostly), the newer the curb, is what I've found so far.

How about the height of the curbing? That factor depends on road speed and its correlation to pedestrian safety. Often, newer curbs will seem very tall (6-8 inches), whereas older curbs are very short. That is often a result of a different safety standards and/or how many layers of pavement have been applied over the years, thereby altering the height of the curb.

A lack of a curb also implies a less formal or a more rural development. I would infer that it is a less expensive method of road construction, since only road subbase and asphalt pavement is necessary, not curbs and sewer drain systems.

Curbs are a subtle element of the built environment and transportation system, but worth noticing because it could be an element that you never think of until it is different. Imagine how your town would look with different curbs, no curbs or the addition of curbs.

A good juxtaposition of concrete curb and granite curb with concrete sidewalk of varying ages, though all relatively recent.

Take a look next time you are out and about. If your town has a different curb, send me a picture! And if you really want to know more about curbs and all related features, read this chapter from the Federal Highway Administration’s guide to Designing Sidewalks and Trails for Access. Or read about curb ramps from FHWA.

13 thoughts on “On Your Streets: Curbs

  1. Jane Griswold Radocchia says:

    curbs are generally used on roads which need to separate people and vehicles. A subdivision built since the 1960’s rarely has sidewalks although there is space for them in the town right of way. (People often believe they own to the pavement, but they don’t.)

    Concrete curbs break up in the freeze and thaw cycle. Asphalt curbs melt and distort in the summer and both will not hurt tires.
    Granite curbs, on the other hand, are a great deterrent in situations where a town wishes to keep cars where they belong because they will cut tires. I have seen them at school entrances to keep a car from going around ( on the right side) the car in front which is waiting to turn left, while pedestrians are also waiting to cross… without the granite a recipe for trouble.
    Granite curbs also serve in tight, often historic, neighborhoods to keep cars from parking on the grass or even the side walk.
    Granite curbing comes in sections. It can and is lifted and repositioned when road repair is done. Unlike concrete or asphalt it has a very long useful life. The quarries are near by In the Northeast so transport costs are not exorbitant..

    did you need to know this much?

  2. Jim says:

    I pay attention to curbs. The ones in the neighborhood where I grew up, along with the sidewalks, were laid by work crews under various New Deal projects and were stamped as such. I live in “old suburbia” now and we have rolled concrete curbs that have sunk in because the storm sewers beneath them are collapsing. Fun times when we get a lot of rain; let’s just see you can’t see the curbs OR the street.

  3. Luke says:

    Don’t forget about southwestern VT, where it is not uncommon to find curbs and sidewalks constructed from marble!

  4. Lmitch says:

    Here in Buffalo, new road construction projects seem to almost always have granite curbs, as opposed to concrete, probably for the same reason as you state above – that snow plows are less likely to damage them. In fact, granite seems to be almost universally-used. Maybe they tried concrete and it just wasn’t good enough for the winters?

    Something I love to notice even more than curbs is sidewalk materials. Here in the older neighborhoods of Buffalo where I live (mostly built in the 1860s and 70s), many of the sidewalks are slate. The size of the slates varies from very small (1′ x 1′) to giant (the whole width of a driveway) depending on the lot. Some are smooth, whereas others are slowly losing layers from the top. They’re all different, which adds subtle character to the neighborhood. In some of its older neighborhoods (I spotted them in Lawrenceville), Pittsburgh has brick sidewalks laid in a herringbone pattern, which are also really cool.

    • Kaitlin says:

      Neat. I love slate sidewalks, too. Often they are slippery, like marble, which is unfortunately one of the problems for safety and ADA compliance. It’d be great to develop a compromise that fits historic preservation issues & compliance. Thanks for the Pittsburgh note — I’ve been, but don’t remember seeing them. Neat! It’s nice to know that the “quaint/charming” brick sidewalks in downtowns sometimes do have a place in history.

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