There is plenty of terminology out there, so this page might help guide you through the minefield of engineer-speak!

20mph Zone/ Limit
A 20mph Zone is an entire area subject to a 20mph speed limit, but where there is traffic calming to help make the speed limit self-enforcing. 

A 20mph limit is the same as any other speed limit, but to implement one, the actual average traffic speeds should be no higher than 24mph.

Zones have their own speed limit signs for the start and end and limits make use of the usual speed limit signs with the need for repeaters as with limits higher than 30mph. A strange quirk as that moving from a 20mph Zone to a 20mph limit still needs the Zone signs which is confusing in my view and possibly because limits have been inappropriate placed without some sort of traffic calming.

A product made by Spanish company, Zicla, which helps provide full or light segregation of a cycle track or zone.

Made of 100% recycled PVC, the Armadillo is a moulded piece which us bolted into the surface of the carriageway.

Advanced Stop Line (ASL)
Sometimes called a bike box or a cycle reservoir, ASLs are stop lines for cyclists at traffic signals which are marked beyond the stop line for general traffic. They are designed to help cyclists pull away in front of traffic and can be quite useful in that regard. Some people don't like them pointing out that they encourage people to filter past traffic when it may not be always safe. They are only lawful if accessed by cyclists by a feeder lane or a little diagonal break in the stop line - the trouble is, the the break is on the nearside, that is where cyclists should enter. My view is the DfT should completely remove the need for the little break completely as it is a waste of time and paint.

Bus Stop Bypass
Also known as a "floating" bus stop. This is an arrangement whereby a cycle track is taken behind a bus stop area so that cyclists don't need to overtake a stationary bus.

Generally the bit motor vehicles drive on (called the road by some). Pedestrians and cycle users have every right to use the carriageway unless prohibited by a Traffic Regulation Order (sometimes used on bridges and tunnels) or if it is a motorway.

Continuous Footway and/or Cycle Track
Where a footway (and/or) cycle track along a main road continues through a side road so that people walking and cycling have priority over traffic. These work best where motorised traffic can only exit a side road so that conflict points are minimised, but they can be used any normal junctions where the kerb-upstand on the main road is kept until the last possible opportunity to keep speeds down. A video of the junction below is here.

Copenhagen-style Bus Stop
A bus stop arrangement often used in Copenhagen, Denmark whereby the passenger boarding/ alighting area is shared with bikes. It is a kind of bus stop bypass where space is tight so that cyclists don't need to overtake a bus.

This is a system whereby an additional traffic signal aspect is added to far-sided signalised pedestrian crossings (standalone or at junctions). When the green man goes out (invitation to cross), the countdown takes over and counts down (in seconds) to the red man. Once the red man is displayed, traffic is released a couple of seconds after. A video showing the sequence for pedestrians is here.

Cycle Junction
Quite simply a "mini" junction for bike riders. Laid out in the same way as a "traditional" UK road junction, the cycle junction works with the usual give way from the side road. A Traffic Regulation Order is required to prohibit general traffic with an exemption for pedal cycles. 

Cycle Lane
A lane painted on the carriageway for cycle users if they choose to use it. Advisory cycle lanes can be encroached into by other vehicles and parked in if no parking restriction is in force. Will be marked with broken white lines. 

Mandatory cycle lanes must not be used by other traffic, but can be crossed to access off street-premises or parking bays behind the lane. Mandatory cycle lanes require a Traffic Regulation Order to be lawful and enforceable and are shown with a solid white line.

Cycle Superhighway
A cycle route which is completely physically separated from motor traffic and wide enough to accommodate the number of people wanting to/ expected to use it. A Superhighway should have priority over side roads, protected traffic signal stages and not interfere with the safe movement of pedestrians. Thanks to Two Wheels Good Blog.

Cycle Track
A "road" provided in or by the side of a highway which has a made up carriageway. Can be in the carriageway, but separated (sometimes referred to as protected) from traffic, on a footway (legally "converted" to a cycle track) shared with pedestrians or segregated from pedestrians, or "grade separated" where the footway is at the highest level, then there is a kerb down to the cycle track and another kerb down to the carriageway (often used in Copenhagen).

Elephant's Feet
Large square road markings which show the direction someone cycling should take through a junction with cycle signals or through a parallel signal crossing or a parallel zebra crossing.

Filtered Permeability
Essentially the creation of access points and junctions which can only be used by cyclists (other traffic excluded) in order to create an open cycle access network so that users can get advantage over motorised traffic. An area reviewed for filtered permeability would end up with no through route for traffic (which would need to stick to main routes), but completely accessible for cyclists. Filtered permeability can use road closures, contraflow one-way access for cyclists and point no entries with cycles excluded from the prohibition.

A route for pedestrians away from a carriageway which will have legal status for use and be recorded on the local authority's definitive map. Often a feature of the countryside, footpaths can be found in urban areas. Cycling is not permitted to take place on them.

A paved pedestrian facility provided in or by the side of a highway which has a made up carriageway. Use for cycling not permitted unless converted to a cycle track (see above).

A way over which generally all members of the public have he right to pass and repass without hindrance. May be maintained by public expense (i.e. local highway authority) or private expense (land owner). A highway will have no bearing on who owns the land as it exists essentially as a "legal veneer" over land. A highway authority can regulate who can use a highway and some highways such as footpaths have restricted use status by definition.

Properly known as "road humps" (many people call them speed humps), these are lawful obstructions placed in the carriageway (and sometimes on cycle tracks) to slow traffic speeds. They can be built from all different types of materials and with different arrangements as permitted by the Road Humps Regulations. I have written a whole post about them.

Light Segregation
A cycling "zone" created within the carriageway which offers some physical protection from traffic using parking bays, posts, armadillos, planters or similar. Arrangement still allows cycles access or exit zone.

Low Level Cycle Signals (LLCS)
These are mini versions of full-sized traffic signals, but specifically aimed at people cycling. They can be used to replicate what is happening on the main cycle signals or are sometimes used to give a green before traffic in areas where cycling is mixed with all traffic.

When used at the same time as full-sized cycle signals, they essentially mean people at the cycle stop line don't have to look up whereas the main signals are aimed at those approaching the junction or crossing.

A Special Road which is of restricted use as pedestrians, cycle users, learners and some other users are prohibited.

Parallel Crossing
A zebra crossing which has a pedestrian crossing area and an adjacent and parallel cyclist crossing area. The pedestrian area is formed by the familiar stripes and the cyclist area is bounded by large square road markings (called elephant's feet).

Passenger Car Unit (PCU)
A traffic modelling method to assign a relative weighting of different transport modes relative to cars in terms of space taken up on the road (a little more complicated than that!) which is set at 1.0 PCU. Cycles are often 0.2 PCU (5 bikes per car). Buses and lorries are often taken as 3.5 PCU. The value can vary according to the conditions. There is a suggestion that when looking at the impact on pedestrians an cyclists, HGVs should be given much higher PCU value to reflect the risks they create for vulnerable road users in urban situations.

Known to most people as the footway, the paved area separated from the carriageway by a kerb, pavement is the term for the structural layers of a carriageway, footway or cycle track which are not the surfacing layers.

A pedestrian crossing with the traffic signals on the far side of the junction. (Compare with puffin crossings).

Pegasus Crossing
Named after the mythical flying horse (perhaps keeping the avian theme for signalised crossings), Pegasus crossings are essentially signalised crossings for people riding horses. They can have far-sided (Pelican style) or nearside (Puffin style) signals with a logo of a mounted rider. They will also have a high level push button for riders.

Pelican Crossing
PEdestrian LIght CoNtrolled (yes, that is where the name comes from) crossing is an example of a Controlled crossing where pedestrians push a button to indicate they wish to cross. Traffic is stopped with a red traffic signal and pedestrians are invited to cross with a green man. 

When the green man flashes, pedestrians should finish crossing and for part of the flashing green man, traffic will see a flashing amber signal which means give way to pedestrians if they are still crossing. 

A green signal to traffic allows it to proceed and a red man suggests that pedestrians should not cross. Pedestrian signals are always on the far side of the crossing (far-sided signals). Crossing time is determined by road width. Far-sided signals can be used in junctions, but flashing amber traffic signal cannot. From October 2016, Pelicans were no longer permitted for new schemes and so as old ones reach the end of their lives, the crossing will fade into history. Future options will be near-side signals (Puffin) or far-side signals (Pedex).

Puffin Crossing Pedestrian User-Friendly INtelligent crossing (another bit of engineer's fun) is a controlled crossing where pedestrians push a button to indicate they wish to cross. Pedestrians cross on a green man and a red man suggests they shouldn't cross. Pedestrian signals are on the push button unit (and sometimes replicated on a panel higher up - near-sided signals) and so once they have started to cross, pedestrians do not see any other signals. 

Traffic is held with a red signal and only allowed to proceed on a green with the signals following the sequencing drivers expect at junctions (red, red-amber, green, amber, red). Crossing time is based on road width. Pedestrian detectors can extend crossing time for slower moving people.

Sensors also cancel pedestrian demand if button is pressed and the person crosses on a red man or walks away from the crossing. Puffin crossings can be incorporated into junctions.

An on-carriageway route, which is well-surfaced, through-traffic is prevented and a 20mph speed limit provided. The route should be direct, well signed and traffic flows likely to be less than 2000 PCUs per day. Thanks to Two Wheels Good Blog.

Raised Entry Treatment
A speed table which is built across the width of a side road at a junction. It creates a level crossing surface for pedestrians (and cycle users where part of a cycle track).

A physical, kerbed "island" placed in the carriageway design to assist pedestrians and cycle users to cross the road in more than one stage, but without giving any specific priority. Some people are intimidated by traffic speed and flow and so a refuge can assist in helping them cross. Refuges can create a "pinch point" to cycle users on the main carriageway whereby vehicles try and overtake them just before or through the feature.

Restricted Parking Zone
Rather than clutter our streets with yellow lines and parking bays, we can use a Restricted Parking Zone (RPZ). The arrangement would have the normal Traffic Regulation Order (Traffic Management Order in London), but the need for yellow lines and parking bays is removed. The Zone would need signs giving the restrictions as one enters and a "Zone Ends" sign on the exit.

The RPZ Zone entry signs can include "No Loading" just under the blue/ red circle. The panel at the bottom can be varied to give different times of operation. Where times are not given, the Zone operate 24-7. 

Where "Except in signed bays" is used, the restriction applies everywhere except in the parking bays. The bays need to be signed (can be for parking, loading, blue badge etc as normal), but the "bays" can be "marked" with bollards, planters, different colours paving etc.

Whatever the times of operation, yellow repeater signs are needed as with a normal restrictions and white loading restriction signs are also needed as normal. Where the restriction applies 24-7, then "At Any Time" yellow signs are needed. A RPZ does not reduce signs that much, but gets rid of the paint which is quite visually intrusive and hard to use with some surfacing materials.

A general term in use meaning the carriageway or a term used probably incorrectly meaning "street". Motorways are "special roads" and some highways are "trunk roads", both being of National strategic value. Road tends to be used to explain a situation where motorised traffic is clearly being prioritised over all other modes. The A406 North Circular is clearly a road.

A road marking which reminds motorists of the speed limit. Often used at the entry to and within 20mph Zones as they are classed as "traffic calming features" for the purposes of the rules. Other speeds can be used where the speed limit changes or to compliment repeater signs at the side of the road.

Safety Cameras
A catch-all term for speed cameras and red light cameras. Speed cameras can be fixed (i.e. installed at one place), mobile (in a van, operated by the police) or average (several along a route either fixed or temporary for roadworks). Red light cameras are fixed.

Cameras were traditionally wet film which required removal from the cameras and then developing in the old fashioned way before offences could be checked which meant that film was not always in a camera at any given time. Modern cameras are digital and can continually record offences. Computer technology can read number plates and issue fines automatically.

Speeds are measured by radar, but reference marks are painted on the carriageway surface so that speeds can be manually checked. Loops/ sensors cut into the carriageway are used to detect red light offences, but they can also be used for speed detection. Some speed cameras are forward facing which captures an image of the driver.

Digital cameras can also be set up to detect red light and speed offences at junctions, so people speed on a green or amber signal will be caught.

Shared Space
A street where several functions either share the same space at the same time or sometimes separated in time. For example, a footway may have loading bays on it which are only operational during times of low pedestrian flows or traffic signals separate different movements and modes by space and time.

Shared space can also mean more radical layouts where traffic, pedestrians and cycle users share the same area on a single surface, such as Exhibition Road in London. The concept seeks to blur demarcations between travel modes and enhance the street scene or public realm. If a layout is mainly for people with very limited vehicle access, then the concept might be appropriate.

Signalised Cycle Crossing
A signalised crossing with exclusive space for cycles which may be part of a stand alone crossing or crossings within more complex junctions. People cycling will be provided with their own signals and routes through the junction will be indicted by elephant's feet markings.

Single Surface
A situation where all highway surfacing is at the same level (sometimes called a level surface). For example, a raised entry treatment can be used to create a single surface at a crossing point or the entire width of the highway can be surfaced in the same material and at the same level. Exhibition Road in London is an example of a single surface.

My own view is that in areas dominated by pedestrians and cycle users and to which vehicles only need access for deliveries or premises, then single surfaces can work. For situations where normal traffic flows through the area, I consider them a failure as it is still "business as usual" for drivers and other users remain intimidated by traffic, especially the young, elderly people and those with reduced vision or mobility.

A description applied to a type of speed hump designed to make passage easier and more comfortable for people riding, while slowing down vehicular traffic.

The cross section is nominally a sinusoidal shape in that the ramp starts shallow, gets steep, rounds over and goes back again. Sometimes the ramps to a speed table are built with a sinusoidal profile.

Spatial Protection
A "catch-all" term to describe how space can be used to protect people walking or cycling. For example, footways are a type of spatial protection in that clear space is provided within which people should be able to walk in safety (I say should as people still drive on the footway). Spatial protection can include elements of parking control, bollards, kerbs, barriers and so on. Good levels of spatial protection will be those features which are continuous and don't remove protection where it is needed (also see "temporal protection").

Speed Table
A large road hump across the width of a carriageway (or a cycle track). Has a flat top and can either run kerb to kerb or stop short to leave a channel for water to pass. Used on cycle tracks where grade separated from the footway to provide a pedestrian crossing point. Can be used to provide a level surface at pedestrian/ cycle crossings of carriageways. If used on a separated cycle track crossing a carriageway, cycles can be given priority over traffic. Sometimes used at a junction in the side road or across the entire junction.

Describes the full function of a highway, especially where traffic flow is less important and a sense of place or other activity is equal or more important. Road names are a fair clue "High Street" is a common UK road name, more famously Oxford Street in London  has function beyond just traffic flow. 

Stepped Cycle Track
Sometimes called a "hybrid", stepped cycle tracks have a kerb upstand above the carriageway and the footway has a kerb upstand from the cycle track.

In highway engineering, there are three main uses:
Tactile paving (or surface) is a textured surface which gives different information to blind and partially-sighted people. UK guidance available here.

Tactile Cone
A tactile cone is a small inverted metal cone placed under the push-button unit of a signalised pedestrian crossing, either at a junction or stand alone. When a green man is displayed, the cone rotates and can be felt by people who may not be able to see the green man or hear the audible signal (if there is one). Cone only rotates when green man shows.

Tactile sign is a traffic sign or a sign on a building aimed at blind or partially-sighted people. May have information as a relief or in Braille.

Temporal Protection
A "catch-all" term to describe how time can be used to protect people walking or cycling. For example, signalised crossings are an example of temporal protection in that time within a junction or on the road is provided within which people should be able to cross in safety (I say should as people still pass through red signals). Temporal protection can include elements of traffic signals, zebra crossings, streets restricted by times of day. Good temporal protection is generally required where people need to negotiate traffic at the same level - i.e. at "grade" (also see "spatial protection").

Toucan Crossing
Two CAN cross (sigh!). A crossing for use by pedestrians and cycle-users at once. Will often be wider than a pelican or a puffin and will often have push buttons on both sides for pedestrians. 

Can use far-sided or near-sided signal arrangements for users and will have detectors like puffins. Traffic will always see the same sequence as for a puffin crossing. Toucan crossings can be incorporated into junctions.

Traffic Regulation Order (TRO)
A legal instrument used by highway authorities to control, manage, prohibit or direct traffic using streets or roads under the Road Traffic Regulation Act 1984. Implemented following a formal process and will end up set out in a signed and sealed legal document. Users will know that a TRO is in place by the presence of signs giving effect to the order (such as speed limits, no entry, cyclists only, parking places, banned turns etc). London has slightly different provisions under the Act and TROs are known as Traffic Management Orders (TMO) - London has lots of little legislative quirks!

Trixi Mirror
A convex mirror attached to traffic signals to help drivers (especially HGVs) to see down the side of their vehicle for the presence of people on cycles, especially before turning left. They are popping up all over the place, but I am not a fan as they are being used rather than sorting out left turning conflicts.

Visual Priority
In the UK, we have "traditionally" laid out road junctions so the carriageway between the roads joining the junction connect there therefore "break" the footways (i.e., the footways go round the corners and one has to cross the carriageway). Where we are looking to continue footways and indeed cycle track across junctions (side roads in particular) it is becoming increasingly clear that visual priority is needed (continuous footways/ cycle tracks and blended junctions are other relevant terms) . Visual priority uses highway layouts and materials which clearly show that footways and cycle tracks have priority. The technique also applies to continuing footways and cycle tracks over private driveways. 

Kerbs and yellow lines which continue around the corners of junctions work against visual priority as they create the impression of a traditional road layout. Visual priority works best when footways and cycle tracks are in materials which contrast with those of the carriageway. It is also important to keep the levels of footways and cycle tracks consistent and have the carriageway rise to take traffic over them, reinforcing the point that the driver is a visitor in someone else's space. It is also possible to use planted buffer strips and other features to further reinforce the point.

Wig-Wags (Conventional)
A type of traffic signal which is used to control traffic at railway level crossings, lifting or swinging bridges, airfields and outside emergency services stations. When the pair of red lights alternately flash, something will be happening ahead and people must stop. In many cases, a barrier will descend to control the way ahead. The lower amber lamp will show just before the red flashing lamps commence.

Wig-Wags (Crossing Patrol)
This is a traffic sign which means "children likely to be crossing the road on their way to or from school ahead". I am sure that there are local names all round the country, but in my neck of the woods, we know them as "wig-wags". Always seen with the children warning sign, they have a sub plate stating "Patrol" where a crossing patrol (lollipop) operates ahead or "School" if a school ahead (sometimes the sub plate will state "disabled children", but not seen so much these days).

I think they are quite useful where there is likely to be a short burst of children/ parents/ carers walking to and from school, but where a formal crossing wouldn't be used at any other times.

A decent set up with have a wireless programming feature to allow a year's worth of term times to be programmed into the controller so the amber signals stay off during school holidays.

Zebra Crossing
Come on, really? A controlled pedestrian crossing with black and white stripes on the road running across the pedestrian walking line. Belisha beacons on top of black and white striped posts which flash yellow. Pedestrians get priority by stepping onto crossing. 

For zebra crossings which can be used by people cycling, see "Parallel Zebra Crossing" above.

In Australia, a humped zebra crossing is called a "Wombat Crossing"!