Road freezingWhat is (Romentoketsu)?temperature Below freezingbecome道路Moisture on top (productsnowAnd fall(I.e.After that, the puddle, etc.) freezes.

In Japan, the frozen road surfaceGermanでSkating rinkMeansice burn(de: Eisbahn).

(I.e.

Automobile

Traffic volumeA lot ofcurve,BridgeUp,交 差点And so onTraffic accidentBecause it causes道路As a measure on the sideFreezeFor preventionCalcium chloride(Also called "salt cal")Snow melting agentSprinkle^[1],Road heatingMelts ice and snow,sandSuch as sprinklingGlidingPreventive measures have been taken.If the temperature is expected to drop early in the morning to the extent that the road surface freezes, it will start in the middle of the night (although it is the "water" that is the target of freezing).Snow pipeIs also performed early to keep the road surface wet.Also,AutomobileAs a measure on the sideス タ ッ ド レ ス タ イ ヤWearing, ice-burn compatibletire chainFor example, wearing.

Pedestrian

When the road surface freezesFallTo increase the possibility of walking, reduce the stride length and walk soon, so-calledPenguinWalking is effective.Some local governments in Japan^[2]Besides, Germany^[3]But it is recommended.

Relationship with temperature

On a completely frozen road surfacesolidOf the ice itselfCoefficient of frictionIt's not very low and the vehicle doesn't slide in particular.sunshineAlthough it depends on the wind, the traffic volume of the vehicle, etc., it becomes dramatically slippery due to the formation of a melted water film on the surface in the temperature range of about 0 ° C to several degrees below freezing.Hydroplaning phenomenonSee also section).Snowfall areas in Japan have a lot of snowfall, but the temperature is not so low, and it is an area where slippery road surfaces are likely to appear in the world.In cold regions below freezing and in high latitudes where there is not much water supply due to snowfall, it does not slip as much as in Japan.

Types of road surface freezing

Snow-packed ice barn

Vehicles passing by repeat the snow that has fallen by its weightcompressionThen,densityOn the road surface with a high layer of snowSnow-packed ice barnOrSnow pressureJust sayNATUREIt is distinguished from a road surface that is just frozen.The hardened surface does not have a snow column shear force and has a low coefficient of friction.

After the midwinterDaytimeThe surface of the compressed snow melts and water collects, and the waterNightWill freeze in^[4]..If this continues repeatedly, the surface layer becomes completely ice (ice burn).

Mirror Burn

dustHolds a metal pin for the purpose of preventing health damage caused bySpike tireThe use of winter tires is prohibitedStudlessWhen I moved to, the tires were polishedMirror surfaceYou can see the snow pressure^[4]..This in particularMirror BurnCalled.It is formed in proportion to the traffic volume at low temperatures, but a minute gliding occurs at each start and stop, and the heat of the underside of the vehicle melts the snow surface slightly while waiting for a traffic light.交 差点Occurrence is remarkable before and after.When mirror burn is used, the effect of the snow melting agent and the grip of the studless tire are significantly reduced.As a countermeasureRoad heatingHowever, due to the high initial cost and maintenance cost including electricity cost, many are installed on the surface to crush the snow pressure by the weight of the vehicle.rubberMoved to pasting the board.

Black ice burn

Thin on the road氷The film is formed and it looks black like a mere wet road surface, but it is frozenBlack ice burnTo say^[4]..At first glance, they often do not notice that they are frozen, which is especially dangerous at night.

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