Whose Turn Is It Anyway?

Solution

A 4-way virtual driving event for people who are good at directions.

You are part of a team of 4 cars, traveling through the Texas landscape from these starting positions using Google Maps Street View (click links for maps):
1. Car 1 -- DODGE – Heading N on Chickasaw Dr (El Paso) Google Street View
2. Car 2 -- FORD -- Heading NE on Almarion Way (Austin/Rollingwood) Google Street View
3. Car 3 -- JEEP -- Heading N on Tierra Blanco Trail (Cedar Park) Google Street View
4. Car 4 -- TESLA -- Heading N on Sebastian Ln (Horizon City) Google Street View
Throughout this event, consider the information on Google Maps Street View to be correct and canonical. The only streets and portions of streets that exist for purposes of this event are those that you can travel on in Google Maps Street View (most, but not all, of which are named). You may want to keep the Street View portion at the top of your screen and the navigation map view, with blue lines showing where Street View exists, at the bottom, which is how the links above will open up. For all purposes, use street names indicated by street-naming signs visible in Street View, and always ignore North, South, East, West, and the abbreviations N, S, E, W when appearing at the beginning of a street name. (There is no trickery here – street names and signs are not always consistent as to such matters.)
Each car on the team must complete a different one of the Instructions 1A, 1B, 1C, and 1D. Instruction 1A must be done completely before 1B, which must be done completely before 1C, which must be done completely before 1D. Importantly, that this means a fact that existed when Part A of an Instruction was being worked on might be different when Part B of the Instruction is thereafter being worked on. Then, all four cars move on to Instruction 2, each taking exactly one of 2A, 2B, 2C, and 2D, all different, and performed one at a time in A, B, C, D order. Continue in this manner until all Instructions have been completed. After finishing an Instruction and until it is time to consider its next Instruction, a car slows down so that it does not pass any intersections or other landmarks that might be relevant to its next Instruction.
The same car cannot perform an Instruction having the same letter designation in 2 consecutive rounds. For example, if a car performs Instruction 1A, it cannot perform Instruction 2A. But after performing, for example, 1A and then 2B, it may perform Instruction 3A – it does not need to do a full set of A, B, C, D Instructions before repeating a letter.
A car must comply with the currently active portion of its currently active Instruction at the first opportunity it can – thus, if a car is currently instructed to “Turn right at an intersection,” it must do so at the first opportunity it can. Note in particular the difference between “Turn right at the first intersection you encounter” (which necessarily can *only* be done at the first intersection you encounter) and “Turn right at an intersection” (which can be done at the second intersection, if the first intersection only allows a left turn and thus the second intersection was in fact the soonest you could “turn right at an intersection”). Do not comply with an Instruction that would cause you to:
1. travel through 15 or more consecutive intersections without turning at any of them;
2. reach a T intersection that you approach from the stem of the T (that is, a place where a cross-street extends to the left and to the right, but where you cannot proceed generally straight ahead) where you are not instructed to turn; or
3. reach a dead end where you cannot proceed without turning around.
If any of a, b, or c happens, you are off-course due to selecting an incorrect Instruction or performing an incorrect action, either in your current round or possibly an earlier round.
The term “Xth” takes the appropriate suffix for whatever number X is. For example, if instructed “Turn right at Xth intersection,” and X is 1, the Instruction means “Turn right at 1st intersection,” despite the “th” in the Instruction. An intersection is a place where a car could proceed in more than one direction without making a U-turn – such as left or forward; or left or right; or left or right or forward; among other combinations. A simple bend or angle in a roadway where a car does not have a choice of 2 or more alternative paths is not an intersection, even if it is 90 degrees and/or even if the street name changes in the bend or angle. If a street to the right and to the left both meet the street you are on at essentially the same place (such as within about a car length), consider that area to be a single intersection even if the streets do not line up precisely. A single street divided by a median remains a single street, even if it appears as two blue lines on Google Maps. (This information is all intended to be helpful only – the situations you encounter should never be unclear or subject to reasonable debate.)
A “cross-street” is a Street View-accessible street (which may be (a) named or unnamed and/or (b) a traditional street or a driveway) at an intersection that extends to your left, to your right, or both, relative to your direction of travel. While some people, outside the event, may make a distinction between “cross-street” (all the way across) and “side-street” (one side only), for purposes of this event and simplicity of notation the term “cross-street” encompasses both types streets a car might turn onto.
Each car carries a scratchpad that is blank except for things the driver is instructed to add to it. Individual letters are always added to the scratchpad in order. If a scratchpad has 4 letters and you add another, that new letter is the 5th letter on the scratchpad.
Finally, and importantly, you may find it useful to read through all of the numbered Instructions below before proceeding, and/or if you find yourself using brute force to examine excessively branching paths. There is only one way to complete the course while following all Instructions, and in some cases, especially in the second half of the event, the correct path cannot be deduced by considering only the current round of Instructions -- some degree of looking ahead to later Instructions is required. While determining the correct route efficiently will require careful logic, nothing is intended to be unclear, ambiguous, or a language trick -- interpret things in the most natural way possible.

Happy Motoring!

1. Turn right at the first intersection you encounter; then travel straight (without turning) through the next three intersections you encounter. (In case it matters, remember that a bend or angle in a roadway, which does not present a choice of paths to follow, is not an intersection.)
2. Turn right at the second intersection you encounter; then travel straight (without turning) through the next two intersections you encounter. (In case it matters, remember that a bend or angle in a roadway, which does not present a choice of paths to follow, is not an intersection.)
3. Turn left at the first intersection you encounter; then travel straight (without turning) through the next two intersections you encounter. (In case it matters, remember that a bend or angle in a roadway, which does not present a choice of paths to follow, is not an intersection.)
4. Turn right at the third intersection you encounter; then travel straight (without turning) through the next intersection you encounter. (In case it matters, remember that a bend or angle in a roadway, which does not present a choice of paths to follow, is not an intersection.)
1. Turn right at the Xth intersection you encounter, where X is the number of the car on the alphabetically earliest street, onto a street with at least 6 letters in the first word of its name.
2. Turn right at the Xth intersection you encounter, where X is the number of the car on the alphabetically earliest street, onto a street with at least 6 letters in the first word of its name.
3. Turn right at the Xth intersection you encounter, where X is the number of the car on the alphabetically earliest street, onto a street with at least 6 letters in the first word of its name.
4. Turn right at the Xth intersection you encounter, where X is the number of the car on the alphabetically earliest street, onto a street with at least 6 letters in the first word of its name.
1. Turn right at the first intersection you encounter; then turn right at the third intersection you encounter thereafter.
2. Swap car numbers with the car that performed Instruction 3A (that is, your number now belongs to the other car, and the other car’s number now belongs to you).
3. Turn right at the first intersection you encounter.
4. Add your car make’s first letter to your scratchpad; then swap car numbers with the only car that is on a street alphabetically later than the street you are on.
1. Travel straight (without turning) through an intersection with a cross-street starting with the same letter as the street that one of your teammates is currently on; then turn left at the first intersection you encounter thereafter. (In case it matters, this is a reminder that (a) the term “cross-street” encompasses streets extending on one side, as well as streets extending on both sides – see Paragraph 6, above; and (b) when an action is directed at an indefinite location -- such as “at an intersection” as opposed to “at the first intersection you encounter” -- it is to be done as soon as it can be done, but not necessarily at the first intersection you encounter.)
2. Add your car make’s first letter to your scratchpad; then swap car numbers with the car that performed Instruction 4A; then turn right at an intersection having a standard STOP sign that controls traffic traveling in your direction.
3. Add your car make’s first letter to your scratchpad; then swap car numbers with the car that performed Instruction 4A; then turn right at the Xth intersection you encounter, where X is the current number of the car that performed Instruction 4B.
4. Turn right at the Xth intersection you encounter, where X is the current number of the car that performed Instruction 4C.
1. Turn right onto a street that is alphabetically earlier than all of the streets that your teammates are currently on.
2. Add to your scratchpad the first letter of the street on which one of your teammates is currently traveling most nearly vertically (north or south) on the map (it shouldn’t be a close call); then travel straight (without turning) through an intersection having a cross-street starting with a letter currently appearing on any of the team’s 4 scratchpads; then turn right onto a street starting with a letter currently appearing on any of the team’s 4 scratchpads.
3. Add to your scratchpad the first letter of the cross-street at the first intersection you encounter; then travel straight (without turning) through that intersection; then turn left onto a street starting with the first letter of a street that another car is currently on.
4. Turn right at the first intersection you encounter.
1. Turn left at a T intersection that you approach from the stem of the T (that is, a place where a cross-street extends to the left and to the right, but where you cannot proceed generally straight ahead); then turn left at an intersection where the cross-street starts with the same letter as the street you are turning off of.
2. Turn right onto a street starting with a letter appearing on any of your team’s 4 scratchpads.
3. Turn right at the first intersection you encounter; then turn right at a T intersection that you approach from the stem of the T (that is, a place where a cross-street extends to the left and to the right, but where you cannot proceed generally straight ahead); then travel straight (without turning) through the first intersection you encounter thereafter.
4. Travel straight (without turning) through the first intersection you encounter; then turn right onto a cross-street that starts with a letter appearing on any of your team’s 4 scratchpads; then turn left at an intersection; then add to your scratchpad the first letter of the only street that one of your teammates is on that does not start with a letter already on any of your team’s 4 scratchpads.
1. Turn right onto a cross-street starting with the same letter as the cross-street of an intersection you traveled straight (without turning) through after this Instruction became your active Instruction.
2. Add to your scratchpad the first letter of the cross-street at the Xth intersection you encounter, where X is the car currently on the alphabetically earliest street; then travel straight (without turning) through that intersection.
3. Travel straight (without turning) through the first intersection you encounter.
4. Turn right at an intersection onto a street alphabetically earlier than the one you are turning off of; then turn left at the first intersection thereafter.
1. Travel straight (without turning) through an intersection controlled by standard traffic lights.
2. Travel straight (without turning) through the first two intersections you encounter.
3. Add to your scratchpad the first letter of the street that the car that performed Instruction 8B is on.
4. Travel straight (without turning) through the first intersection you encounter; then swap car numbers with the car that performed Instruction 8C.
1. Turn left at the third intersection you encounter.
2. Travel straight (without turning) through an intersection with a cross-street whose name starts with a vowel (one of AEIOU).
3. Travel straight (without turning) through an intersection with a cross-street whose name contains 2 consecutive instances of a letter that does NOT appear on any of your team’s 4 scratchpads.
4. Travel straight (without turning) through an intersection; then turn right onto a cross-street having a name alphabetically later than the name of the street you are turning off of; then, at the first intersection thereafter that you encounter, add to your scratchpad the alphabetically latest letter contained in the name of the cross-street at that intersection as it appears on its street-naming sign; then travel straight (without turning) through that intersection.
1. Turn left at the third intersection you encounter; and then turn in the only direction possible at an intersection where the cross-street starts with the same letter as the street you are turning off of.
2. Travel straight (without turning) through the first intersection you encounter; then make your first left turn of the event by turning left at an intersection thereafter.
3. Turn left at an intersection.
4. Turn left at an intersection having a standard STOP sign that controls traffic traveling in your direction.
1. Radio your teammates to confirm they are having as much fun as you are!
2. Turn right at the first intersection you encounter.
3. Turn left at an intersection controlled by standard traffic lights; then turn left thereafter at an intersection controlled by standard traffic lights.
4. Radio to each of your teammates asking them to report the Xth letter of the Xth word in the full, unabbreviated name of the street they are currently on (if possible for them to do so), where X is the number of their car, and after they correctly comply (if possible for them to do so) add to your scratchpad the only reported letter that does not already appear on any of the team’s 4 scratchpads; then observe that you do not have exactly the same number of letters on your scratchpad as any of your teammates has on theirs; then travel straight (without turning) through an intersection thereafter with a cross-street extending only to your right; then travel straight (without turning) through an intersection thereafter with a cross-street extending only to your left.
1. Turn right onto a street starting with the third letter on the scratchpad of the car that performed Instruction 11A.
2. Turn right onto a street starting with the third letter on the scratchpad of the car that performed Instruction 11B.
3. Turn right onto a street starting with the third letter on the scratchpad of the car that performed Instruction 11C.
4. Turn right onto a street starting with a letter on the scratchpad of the car that performed Instruction 11D.
1. Turn left at the second intersection you encounter; then park your car on the street you are then on as you arrive at the second intersection you encounter thereafter.
2. Park your car on the street you are on as you arrive at the second intersection you encounter.
3. Travel straight through an intersection with a cross-street extending only to your right (but do not turn there); then travel straight through an intersection thereafter with a cross-street extending only to your left (but do not turn there); then turn right at the first intersection you encounter thereafter; then park your car on the street you are then on as you arrive at the first intersection you encounter thereafter.
4. Turn right at an intersection; then turn right at an intersection thereafter; then turn right at an intersection thereafter; then turn left at an intersection thereafter; then park your car on the street you are then on as you arrive at the first intersection you encounter thereafter.

BONUS INSTRUCTION, TO BE COMPLETED BY ALL CARS AFTER INSTRUCTION 13D IS COMPLETED:

Erase everything on your scratchpad;
then write your current car number on your scratchpad, followed by the first word of the name of the cross-street (not the street you are on), as shown on a street-naming sign you can currently see;
then collaborate with your teammates as to the answer to submit for this event;
then submit a correct answer;
then rejoice in your well-deserved victory!